The Northern Territory Chief Minister has formally apologised to the LGBTI community for "state-sanctioned discrimination", as Parliament passes legislation allowing historical homosexual convictions to be struck from records.

Speaking in Parliament on Tuesday, Michael Gunner emotionally apologised not only for the law that "criminalised love and attraction" between same-sex couples until 1983, but for the opportunities stolen from those convicted.

A bill to expunge the records of those historically convicted of consensual homosexual sex was passed on Tuesday afternoon, but those with convictions will have to apply to have it removed.

It is believed about a dozen men were charged under the old laws, and it is not known how many are still alive.

"Today is about making right," Mr Gunner started his speech.

"It is about making right on hurtful and discriminatory laws tolerated, supported or actively perpetuated by Northern Territory governments.

"Today is about saying to our lesbian, gay, transgender, bisexual, intersex and queer community: We were wrong.

"Laws criminalising homosexuality were wrong.

"Laws criminalising love and attraction were wrong.

"And historical convictions stemming from these laws were — are — wrong.

"Today we pass laws so that these convictions may be struck from personal records."

Michael Gunner was emotional as he spoke about his sister during the apology. ( ABC News: Alan Dowler )

He acknowledged the shame the laws caused and the damage they inflicted, along with the job and travel opportunities lost because of the criminal records.

"Words are powerful — like in the Criminal Law Consolidation Act 1876, which the Territory adopted from South Australia and used all the way until 1983," Mr Gunner said.

"Tucked in between laws about kidnapping and incest is this: 'Whosoever shall be convicted of the abominable crime of buggery, committed either with mankind or any animal, shall be liable to be imprisoned for life with hard labour.'

"The brutality of that language — 'the abominable crime of buggery' — the equating of homosexuality with bestiality.

"This was the law of the land until 1983, within most of our lifetimes.

"The brutality of that language. More so, the brutality of the message: You are not worthy. You are not welcome. You are an abomination."

Government 'openly hostile' to the LGBTI community

He spoke about a conversation he had with a man who described how a criminal conviction had shaped his life and the lives of his friends.

"A Darwin man, who asked to stay anonymous, told us recently 'I was 17 and living with an older man. We lived in constant fear of him going to jail. And that was a relationship that lasted 15 years, not some fling'," Mr Gunner said.

He also described the experienced of Annie Zon, who moved to the NT in 1980 and found a government "openly hostile to same-sex attracted women".

"There was this jingoism at the time about what it was to be a Territorian, she says. And what it was to be a Territorian was not to be a lesbian," Mr Gunner recounted.

"Sometimes when they were arrested they were they were quite brutally treated by police. Physically manhandled. Verbally insulted. Told they were dirty lesbians and they should leave town and they were hateful creatures, that no-one wanted them here."

He said as recently as the early 2000s Daniel Alderman, a champion of LGTBQI rights in the Territory, marched with a dozen people at a pride rally and had water bottles thrown at them by people sitting at a pub.

NT Parliamentarians celebrate the historic day, with cake. ( ABC News: Jano Gibson )

"He remembers, quote, horrific stories of police harassment," Mr Gunner said.

"I'm proud to say Daniel marched in last year's Pride Festival with about 1500 people, including police, including the Commissioner of Police. No-one threw water bottles."

Mr Gunner welled up as he said "Australia has come so far — later this year I will be a proud brother at my sister Lucy's wedding to her long-time partner Jill".

Going forward, he hoped to see the "last vestiges of homophobia and transphobia" removed from NT laws.

"Let's work together so government is a force for inclusion, not discrimination," he said.

Opposition Leader echoes apology

The apology was supported by Opposition Leader Gary Higgins, who acknowledged the NT was one of the last jurisdictions in Australia to expunge historic convictions for homosexual conduct.

"As the leader of the Opposition in this Parliament, I offer my formal apologies to those who today have criminal records for being in a loving and consensual relationship," he said.

"It is about time to pass this legislation, and once more, on behalf of the Opposition, to those who today suffered under these past laws and convictions, we say sorry."

Opposition Leader Gary Higgins supported the new legislation and the apology to LGBTI community members. ( ABC News )

Hope apology will lead to broader social change

Darwin LGBTI community members Caitlin Perry and Matthew Van Roden watched from the public gallery as Mr Gunner made the apology, and each said they found it moving.

"It was wonderful," Mr Van Roden said.

"Moving speeches and interesting to reflect on how recent the history is that we're dealing with today. It was moving for me."

Ms Perry hoped the legislative change would lead to broader social change regarding attitudes towards LGBTI people.

While she described the apology as "symbolic" she said that should not detract from its importance.

"I think symbolism makes a huge difference in terms of people's lives," she said.

"I mean, all of us here will have suffered discrimination regardless of what the law said, in quiet ways and in loud ways.

"In workplaces, in public transport, in public spaces and in our families, so [the apology is] actually really, really powerful."

Mr Gunner said the law "criminalised love and attraction" between same-sex couples. ( AAP: Carol Cho )

Anna Brown, the director of legal advocacy at the Human Rights Law Centre, said the apology was a "hugely important step forward" towards removing the stain of discrimination and prejudice embedded in historic Territory laws.

She said those laws had created a climate of fear and prejudice.

"It meant that LGBTI people felt as though they were criminals, well they were criminals," Ms Brown said.

"I guess this meant that socially people felt excluded, they felt isolated, they couldn't be free to be themselves.

"And what today's done is sent a clear message that this government values LGBTI people, it values difference, and differences in sexuality and that's a very welcome step."

She said it made sense that an application would be required to have a record expunged, as the historic law related to both consensual and non-consensual sexual acts.

"But it's important that it's accessible, it's confidential, we're not re-traumatising people who've already suffered too much trauma at the hands of the state. But that's why the blanket approach is inappropriate," she said.