There are three types of employment contracts in the federal system: the law is now included in the Trade Union and Labour Relations (Consolidation) Act 1992 s.179, under which collective agreements are definitively considered non-binding in the United Kingdom. This presumption can be rebutted if the agreement is written and includes an express provision that it should be legally enforceable. By May 2004, AEAs had achieved coverage of about 2.4% of the workforce.  Mining companies have advanced the agreements with some success and have offered substantial wage increases to workers who have opted for an AWA. To avoid confusion and misunderstanding, it is important to ensure that the labour agreement contains all claims in the NES. Where a clause in an employment contract provides a less favourable right to a worker than the equivalent right in the NES, the law applies under the NES and can be enforced by the worker regardless of the terms of the contract. It is important to understand the difference between a common class agreement and an employment contract. While there is a common law contract when you mandate a worker, whether it is an oral or written contract, the term employment contract, as used in labour law, refers to a formal document containing certain clauses and formally submitted to a public authority. The most common type of labour agreement in agriculture is the single enterprise agreement, which is an agreement between a single employer and its workers or a group of workers. AEAs give employers and workers flexibility in setting wages and conditions and allow them to enter into agreements that correspond to their workplace and individual preferences. AWAs offer employers and employees the opportunity to enter into an agreement that best meets the specific needs of each employee. An existing employee may not be required to sign an AWA.
 In April 2007, the Sydney Morning Herald reported receiving unpublished government tables that showed that 27.8% of the agreements had eliminated the conditions that were to be protected by law.   The tables were based on a sample of AWA agreements.  The three types of employment contracts that can be concluded are: according to OAS statistics, as of 31 December 2004, 1,410,900 persons were covered by EU-certified agreements, 168,500 by non-union agreements and 421,800 or more than 21% by ASA. As of December 31, 2005, there were 1,618,200 under the Union Certified Agreements, 185,300 under non-union agreements and 538,200 Australian enterprise agreements.  Figures published in March 2005 by the Australian Bureau of Statistics show that hourly wages for workers in AWAs were 2% lower than workers` hourly wages in registered collective agreements, which were mainly negotiated by trade unions.  For women, AEAs paid 11% less per hour than collective agreements.  The decision to obtain an employment contract depends on the impact of the corresponding award on your company`s employment needs. Since formally filed employment contracts are instead of bonuses, employers are able to change certain premium conditions that do not meet the needs of their business, provided that workers are not financially worse off than the supplement.