Retainer Agreements for Australian Lawyers: Structure, Billing and Best Practice

A retainer agreement is the foundation of every solicitor-client relationship. It defines what the lawyer will do, how much it will cost, and what happens if things go wrong. Yet many Australian lawyers — particularly in smaller firms — rely on informal arrangements, verbal agreements, or templated documents that have not been updated in years. The consequences of this casual approach only become apparent when a billing dispute arises or a professional conduct complaint is made.

This guide covers how to structure effective retainer agreements, the distinction between retainers and costs agreements, and the specific requirements imposed by Australian legal professional regulations.

Retainer vs Costs Agreement: Understanding the Distinction

The terms "retainer" and "costs agreement" are often used interchangeably in practice, but they refer to different things.

A retainer agreement (also called a letter of engagement or client agreement) is the overarching document that establishes the solicitor-client relationship. It covers the scope of work, the responsibilities of each party, confidentiality, conflicts of interest, file management, termination provisions, and complaints procedures. It may incorporate a costs agreement or address costs within its terms.

A costs agreement is specifically about money — how fees will be calculated, the applicable rates, the billing frequency, and the client's rights regarding costs. Under the Legal Profession Uniform Law 2014, a costs agreement is defined in section 174 as an agreement about the payment of legal costs.

In practice, most firms combine both into a single document. This is perfectly acceptable, provided the document addresses all the requirements of both the retainer and the costs disclosure obligations. For more detail on the disclosure requirements, see our article on costs disclosure obligations for Australian lawyers.

Types of Retainer Arrangements

Matter-specific retainer

The most common type. The firm is engaged to handle a specific legal matter — a property transaction, a litigation matter, an employment dispute. The retainer defines the scope of that particular engagement and terminates when the matter concludes. Billing is typically on a time-cost basis at agreed hourly rates, though fixed-fee arrangements are increasingly common for well-defined transactional work.

General retainer (ongoing)

Used primarily by corporate and commercial clients who need regular legal support across multiple matters. The client pays a monthly or annual fee for access to legal services, which may cover a specified number of hours or types of work. Additional work beyond the retainer scope is billed at agreed rates. These arrangements require careful definition of what is "in scope" and what constitutes additional billable work.

Limited scope retainer (unbundled services)

The lawyer is engaged to perform only part of the legal work, with the client handling the rest. For example, a lawyer might draft court documents but not appear at hearings, or provide advice on a property contract but not handle the settlement. Limited scope retainers require particularly clear documentation of what is and is not included, to protect both parties.

Conditional costs agreement

A "no win, no fee" arrangement where the lawyer's fees are contingent on a successful outcome. These are common in personal injury and some commercial litigation matters. The Legal Profession Uniform Law imposes specific requirements on conditional costs agreements, including restrictions on uplift fees (capped at 25% of normal costs) and requirements for clear disclosure of the client's potential liability for the other party's costs.

Essential Components of a Retainer Agreement

A comprehensive retainer agreement should address the following areas. Omitting any of these creates risk — either of a billing dispute, a professional conduct complaint, or a professional indemnity claim.

Identification of the parties. The full name of the client (individual, company, or trust), the law practice, and the responsible solicitor. For company clients, identify the person authorised to give instructions.

Scope of work. A clear description of the matter or matters covered by the retainer. Be specific about what is included and, equally importantly, what is excluded. A retainer to "handle your property settlement" should clarify whether it includes stamp duty advice, trust structuring, or post-settlement disputes.

Costs and billing. The basis for calculating fees (hourly rates, fixed fee, or other), the applicable rates for each fee earner, the billing frequency, payment terms, and the consequences of non-payment. This section must comply with the costs disclosure requirements under sections 174-178 of the Legal Profession Uniform Law.

Estimates. A realistic estimate of total costs, or a range if the matter's scope is uncertain. The estimate should be based on the information reasonably available at the time and should be updated if circumstances change materially.

Disbursements. An indication of the types and approximate costs of anticipated disbursements — barrister's fees, expert reports, court filing fees, search fees, travel expenses. Clients are frequently surprised by disbursements they were not warned about.

Client obligations. The client's obligation to provide instructions promptly, to disclose all relevant information, to respond to correspondence in a timely manner, and to pay bills when due.

Confidentiality and conflicts. Confirmation of the lawyer's duty of confidentiality and the conflict of interest check that has been performed. If a potential conflict exists, it should be disclosed and the client's informed consent obtained in writing.

Termination. The circumstances in which either party may terminate the retainer, the notice required, and the client's obligation to pay for work performed up to the date of termination. Include the firm's lien over documents in the event of non-payment.

Complaints. Information about the firm's internal complaints handling procedure and the client's right to contact the Legal Services Commissioner.

Billing Under a Retainer: Practical Considerations

The way you structure billing within a retainer agreement directly affects both revenue and client satisfaction.

Monthly billing is the standard. For ongoing matters or general retainers, monthly invoicing provides regular cash flow, prevents bill shock, and gives the client visibility over accumulating costs. Bills should be issued within the first week of the following month.

Milestone billing suits transactional work. For matters with clear stages — conveyancing, corporate transactions, estate administration — billing at the completion of each stage can be more appropriate than monthly billing. Define the milestones and the fees for each in the retainer.

Trust account deposits. Many firms require a deposit into the trust account before commencing work. This is legitimate provided it is properly documented in the retainer and the funds are held and managed in accordance with the trust account provisions. The amount of the deposit should be proportionate to the anticipated initial costs.

Interest on late payments. If the retainer provides for interest on overdue accounts, the rate and the calculation method must be specified. Interest clauses that are excessive or punitive may be unenforceable under the Australian Consumer Law or the relevant unfair contract terms legislation.

Common Retainer Mistakes

Scope creep without updated documentation. The matter expands beyond the original scope but the retainer is never updated. When the bill arrives, the client argues they never agreed to the additional work. Always document scope changes in writing and provide updated costs disclosure.

Failing to identify the client. In family or small business matters, it is not always obvious who the client is. A retainer addressed to both spouses in a property purchase, or to a company director personally rather than to the company, creates confusion about who is responsible for fees and to whom duties are owed.

Template overload. A 20-page retainer agreement for a $3,000 matter is disproportionate and unlikely to be read. Scale the document to the matter — a brief letter of engagement with key terms is sufficient for simple matters, while complex commercial retainers justify more detailed documentation.

Not sending the retainer before starting work. The retainer should be signed before any substantive work begins. Lawyers who start work on the understanding that "the paperwork will catch up" create unnecessary risk and may compromise their ability to enforce the costs agreement.

Record Keeping and the Retainer

The retainer agreement sets the framework, but it is the time records that prove the work was done. Detailed, contemporaneous time recording is essential for justifying bills under any retainer arrangement. Entries should reference the specific matter or sub-matter, identify the fee earner and their rate as specified in the retainer, and describe the work in sufficient detail that the client can verify it against the agreed scope. For guidance on effective time recording, see our guide to recording time as a lawyer.