Allowing terminally ill patients to end their lives does not lead to a slippery slope of legalised dying, an American expert says.

Debate was rekindled this week after Auckland man Evans Mott was discharged without conviction for pleading guilty to assisting his wife to commit suicide.

Labour MP Maryan Street has drafted a member's bill that would make it legal for people who are terminally ill or suffering from an irreversible disease to take their own life or have someone help them to die.

The bill has to be drawn from the members' ballot before it can be debated in Parliament.

A poll out yesterday showed almost 63 per cent of people supported the move.

The online Horizon poll of 2969 respondents found 62.9 per cent supported the law change while 12.3 per cent were opposed.

Almost 65 per cent of people said they would want the option available to them if they were terminally ill, while 39.9 per cent said they would help a close friend or relative to end their life.

Yvonne Shaw, the former director for Compassion & Choices of Oregon, said New Zealanders should review the impact of similar laws in other countries.

In Oregon, and neighbouring Washington State, the number of aid-in-dying deaths was less than 1 per cent of all deaths.

In Belgium it was less than 2 per cent.

"The emergent trend is reassuring to those who fear the slippery slop dynamic. The slippery slope argument contends that passing a law to legalise aid-in-dying would precipitate an avalanche of requests.''

Shaw said a positive unintended consequence of the Oregon law change was that more people were accessing hospice care - about 95 per cent of those in the programme as opposed to an average 60 per cent outside.

"When people call they don't know what their options are,'' she said.

Exact numbers are difficult to collate but about 1200 have entered the programme since 1998, 700 went through with it.

Street said her bill was about making assisted dying legal, not easy.

"I am persuaded that most people want to see an appropriately restrictive law in this area, based on compassion for those suffering from terminal illness or irreversible conditions which in their own view make their lives unbearable.''

Public opinion on the issue was changing, as evident by recent polling, she said.

"Lesley Martin got 15 months custodial sentence, Sean Davison got five months home detention, Evans Mott discharged without conviction.''

Martin was sentenced for the attempted murder of her terminally ill mother and Davison was charged with attempted murder but eventually pleaded guilty to the lesser charge of inciting and procuring suicide.

National MP Maggie Barry opposes Street's bill and said Mott's case had not changed her mind.

"Suicide is not illegal and this case does not change my position on euthanasia.''

- © Fairfax NZ News