The Federal Government has announced an overhaul of anti-discrimination laws, including shifting the burden of proof to the defendant once a prima facie case has been established.

The changes would also expand the protections available under the laws to deal with discrimination on the basis of sexual orientation and gender identity.

In making the changes, the Government plans to consolidate the five current pieces of anti-discrimination legislation into one and introduce a single definition of discrimination to cover all areas.

"It's ridiculous that at the moment an African woman, for example, who has been discriminated against, needs to separately make complaints of sex and race discrimination - now she can make a single complaint recognising the discrimination was because she was both a woman and African," Attorney-General Nicola Roxon said in a statement.

In explaining the changes at a later media conference, Ms Roxon said the overhaul would simplify what standards were required under the law.

"It'll make it easier for people who have been treated badly to make a complaint, and indeed it will make it easier for people who have a complaint made against them to be able to have unmeritorious complaints dispensed with."

One of the proposed changes involves shifting the burden of proof in a discrimination case, a move modelled on the UK approach.

"A person making a complaint has to show a prima facie case - that means they have to be able to first prove the substantial components of discrimination," Ms Roxon said.

"Once that is done, it would then be up to the respondent... to show that it wasn't for the reasons alleged."

Shadow attorney-general George Brandis says while there is a strong case for consolidating anti-discrimination laws, he has expressed concern about shifting the burden of proof.

"We think, as a matter of general principle, the reversal of the onus of proof is a bad thing - it violates the whole principle upon which our justice system has always operated," Senator Brandis told Sky News.

"That is, that 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've done the right thing."

Sorry, this video has expired George Brandis has expressed concern about shifting the burden of proof.

Burden of proof

But Human Rights Commission president Professor Gillian Triggs says changing the burden of proof is a "commonsense" idea.

"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," she said.

"[The proposed legislation] provides greater certainty for business by clarifying the evidentiary requirements for complaints and providing a streamlined ability to reject complaints."

The Greens say they are pleased the Government is moving against discrimination on the basis of sexuality or gender identity, but have taken the opportunity to again push the case for same-sex marriage.

"It's rather ironic that the Government wants to be applauded for including sexual orientation as part of what can be included in anti-discrimination, and yet maintains the discrimination that is there by preventing marriage equality," Greens leader Christine Milne told reporters in Canberra.

"So this ought to be the really big question for Prime Minister Gillard.

"If you're serious about ending discrimination on the basis of sexual orientation, then give us marriage equality."