Julia and Barry Rollings with a photo of their daughter who travelled to the US to get married earlier in the year.

Julia and Barry Rollings at the Legislative Assembly on Thursday with a photo of their daughter's wedding in the US. Photo: Rohan Thomson

"We're here for the rights that one of our kids doesn't have compared to the others," Barry and Julia Rollings said on Thursday.

The Conder couple were at the ACT Legislative Assembly as the territory government presented its marriage equality bill.

In June the Rollings flew to the US to watch their 27-year-old daughter Briony marry her partner Barbara.

Briony and Barbara returned to their home city of Canberra, where their marriage is not recognised.

"When [the laws pass] she would like to have a ceremony here so friends and family can attend," Mrs Rollings said.

"We went to their wedding in the US. But the distance meant that most of her brothers and sisters couldn't accompany her."

Attorney-General Simon Corbell said on Thursday that the passage of marriage equality laws would allow same-sex couples to marry in the ACT by the end of the year.

Deputy Chief Minister Andrew Barr, who is gay and has a long-term partner, said he fought back tears while listening to Mr Corbell endorse the bill. ''We're doing, I think, a really good thing today,'' he said. ''It speaks to our values, it speaks to why we're in politics.''

The federal government has signalled it will seek legal advice on whether the ACT can sanction same-sex marriage.

But despite concerns the laws could face a challenge, the bill was greeted with a standing ovation from supporters in the Assembly's public gallery, many of whom had waited years to see marriage equality legislation introduced in the territory.

O'Connor resident Gabriel Coburn said "if the Commonwealth is not going to do it, it's up to the territory to alter that for the better".

"I came along today because I'm a Labor supporter but I've also been a supporter of marriage equality all my life," Mr Coburn said.

"I've seen a number of my friends in relationships who don't have their relationship recognised by law and it's time to change that."

Ivan Hinton, the deputy national director of Marriage Equality Australia, said on Thursday he was concerned the federal government would try to overturn the laws.

"I think the federal government needs to recognise the ACT's mandate in this regard," he said.

"They [the ACT government] went to the last election, the territory election, with this platform firmly squared and the Canberra population re-elected them."