An agreement is usually broken down into two parts: an offer and an acceptance and involves a 'meeting of the minds' (a consensus) between two or more parties. A contract is an agreement made between 2 or more parties that is legally enforceable.An Overview on Certainty in Australian Contract Law: For a contract to be legally effective, the contract must have sufficient certainty and completeness. This 12th edition continues the tradition of meticulous examination and reexamination of every aspect of the law of contract. Consideration is an essential element in the formation of a contract. Example 1: In order for a contract for the sale of land to be enforceable, it must be in writing. (See, for example, the Property Law Act 1974 in Queensland). The basic principle of Australian contract law is freedom of contract, under which parties are at liberty to strike whatever bargain they choose. Contract law is at the core of almost every lawyer's practice. The Australian Consumer Law protects consumers and small business from unfair contract terms.