Paul Gabrielides made two promises to his wife Anne, just before she died from motor neurone disease in January this year.

Firstly he promised her death would be "a good death" and the second promise was that he would continue to fight to change the laws surrounding voluntary euthanasia in NSW.

He says he let her down on the first promise.

"In six months Anne lost the power of speech, slowly the muscles and limbs lost away," he said.

"[B]ut everyone dies due to respiratory failure, the failure to breathe, their intercostal muscles don't work, the simply can't draw breath.

"It will burn a hole in me forever, for all time, watching that last few hours, no one should see that," said Mr Gabrielides.

Paul Gabrielides will run as a candidate for the Voluntary Euthanasia Party in the NSW state election in March next year. ( ABC News: Supplied. )

Anne and Paul campaigned for voluntary assisted dying laws to be made legal in NSW.

In November last year they lost that battle with NSW MPs voting the bill down.

It was close — after a marathon debate than ran all day and ended close to midnight — but the bill failed to pass the Upper House by a single vote.

MPs were given a conscience vote on the legislation which would allow terminally ill patients over the age of 25 to end their own lives with the help of doctors.

Despite Anne's death, Mr Gabrielides has not given up.

He has announced he is going to run as a candidate for the Voluntary Euthanasia Party in the state election in March 2019.

'I don't think the candidates are just about euthanasia and just about death," he said.

"I think it's about compassion and bringing equality to all people in NSW.

Paul Gabrielides is running for a spot in NSW Upper House next March to push for voluntary euthanasia to honour his late wife Anne. ( Supplied )

The 58-year-old, father of three is a former science teacher and businessman and will join 14 other candidates trying to get a spot for the party in the Upper House.

The Voluntary Euthanasia Party says the most recent national poll of voters shows 85 per cent support assisted dying laws.

Candidate Shayne Higson, started the NSW branch of the party in 2013 after watching her mother die from brain cancer seven months after being diagnosed.

Ms Higson ran at the last NSW election in March 2015 but missed out on a spot.

"Since 2015 a number of other jurisdictions have legalised voluntary assisted dying," Ms Higson said.

"The whole of Canada, some extra states in America, California being the largest, most recently Hawaii, [and] we now have a law in Victoria.

Paul Gabrielides and Shayne Higson, of the Volunteer Euthanasia Party. ( Supplied )

"We are moving in the right direction. There is momentum and our politicians are not keeping up with what the public wants."

To get elected to the NSW Upper House, even in the last seat, parties need at least 1.8 per cent of the vote. The Voluntary Euthanasia Party got less than 1 per cent in the 2015 election, so they need to almost double their vote.

The ABC's Election Analyst Antony Green said there are other factors as well.

"You can get a small vote just by the name of the party and people know what Voluntary Euthanasia Party stands for."

NSW has a system which more than 80 per cent of ballot papers do not have preferences in the Upper House.

Antony Green said "a party needs first preferences to get elected."

Mr Gabrielides knows he has a fight on his hands.

But he's determined because this time he says he's not going to let his wife down.

"I do not want to see any of my loved ones in so much pain."