The Coalition has warned proposed changes to discrimination law which will make it easier for people to make complaints would lead to a huge increase in claims.
Federal Attorney-General Nicola Roxon and Finance Minister Penny Wong on Tuesday released draft laws that would consolidate, harmonise and simplify the five existing Commonwealth discrimination laws and introduce sexual orientation and gender identity as new grounds of discrimination.
The draft bill creates a shifting burden of proof, meaning that once a complainant has established a prima facie case the onus would be on the other party to justify their conduct.
Coalition legal affairs spokesman George Brandis said the change would violate a fundamental principle of our justice system, that a person is innocent until proven guilty.
''If you make an allegation against someone, it's for you to demonstrate that they have done the wrong thing, not for them to prove that they have done the right thing,'' Senator Brandis told Sky News on Tuesday.
''Do we want many, many more complaints tying up the courts, particularly when the onus of proof is thrown on people to prove their innocence? I don't think so,'' he said.
But Ms Roxon said the proposed change did not amount to a reversal of the onus of proof.
''There is a shift in the way the evidence works, but it's not a full reversal,'' Ms Roxon told ABC radio.
''I think actually many business groups will welcome this, because instead of having to comply with five different laws at the Commonwealth level, there will be one. There's new processes that didn't exist before, that organisations can have their human resources policies approved by the commission, and if they're adhered to, that would be a defence to discrimination. It's actually a really good opportunity for people to enhance their processes.''
The Australian Human Rights Commission president Gillian Triggs said it was ''common sense'' to place some of the evidentiary onus on respondents to claims.
''It means that those with the relevant information will be the ones who are required to supply it – this is consistent with other civil claims processes in Australia," Professor Triggs said.
Australian Greens legal affairs spokeswoman Penny Wright welcomed the proposals, but said they should go further to outlaw discrimination on grounds such as ''religious beliefs or activity, irrelevant criminal records and social status''.
''This would mean people could not be discriminated against, for example, if they are homeless or unemployed.''
Senator Wright also said exemptions to discrimination laws available to some religious organisations should be reviewed.
In other proposals in the draft laws, parties would no longer face the risk of being forced to pay the costs of their opponent if they lost, and the Australian Human Rights Commission would get the power to dismiss unmeritorious complaints.
The draft laws contain a single definition of discrimination as ''unfavourable treatment'' and a simple defence of ''justification'', meaning that discrimination is lawful when it is done for a legitimate aim and is proportionate to that aim.
The bill would allow a person who faced discrimination on multiple grounds such as race, gender and age to lodge a single complaint.
The proposals will be the subject of a Senate inquiry before the legislation is introduced to Parliament next year.