The equal marriage bill for the Australian Capital Territory (ACT) is to be altered in order to protect it against a High Court challenge by the Australian federal government.

Earlier this month it was announced that Australia’s federal government planned to challenge the ACT’s same-sex marriage law in the High court.

Legal experts argued that the bill, which is to be debated on Tuesday in the ACT Legislative Assembly, was in danger of being overturned, as it aimed to legalise marriage for any person unable to marry under the federal Marriage Act.

The title will be change specifically to refer to same-sex marriage. It will be clarified to no longer cover transgender couples who do not identify as male or female.

ACT attorney-general Simon Corbell said: “We recognise that the views of a number of constitutional experts are that we should put that issue beyond doubt.”

He went on to say that, if the bill was upheld after being challenged in court, the ACT would look at re-expanding its scope.

ACT Chief Minister Katy Gallagher, said she is committed to having the legislation passed this week, despite calls from federal attorney general George Brandis to halt the bill.

If the bill were passed, same-sex couples could marry as soon as December.

Australian Prime Minister Tony Abbott has said there should be a uniform approach to marriage across the country.

Christine Forster, the sister of Mr Abbott, has revealed that she has proposed to her partner Virginia Edwards.

Equal marriage remains banned at a federal level in Australia.

Efforts to legalise the measure failed in the Australian Parliament last year.