Voluntary euthanasia has been knocked back in South Australian Parliament for the 15th time after a marathon late session in the House of Assembly overnight.

Key points: MP's conscience vote tied at 23 votes for and against

MP's conscience vote tied at 23 votes for and against Speaker uses casting vote to defeat bill

Speaker uses casting vote to defeat bill Voluntary euthanasia bills defeated 15 times in SA

The bill initially passed a second reading stage with a vote of 27 to 19, leading to a debate that continued up until about 4:00am.

But the Death with Dignity bill from Liberal MP Duncan McFetridge was examined clause by clause and a conscience vote was tied at 23 votes for and against.

Speaker Michael Atkinson then used his casting vote to decide against the bill and end the debate.

He told 891 ABC Adelaide that he was disappointed that SA Premier Jay Weatherill and Opposition Leader Steven Marshall pushed to have the bill decided in the early hours of the morning.

He said the clause in the amendments were defeated because they were considered by a "group of sleepless and irritable MPs for hours and hours until 4:00am".

"Duncan McFetridge had a very bad six hours in which he was unable to answer most of the questions about this bill," Mr Atkinson said.

"If someone else had been put in charge of the bill, if it had been considered during daylight hours, clause by clause in a patient and sophisticated way, over several days, it may have been carried.

"It's a textbook example of bad legislative practice, to be considering this between 10pm and 4am."

Late debate did not affect outcome, proponent says

Mr McFetridge, however, rejected the late debate as a reason for the bill's defeat.

He said the debate was not over, but a fresh impetus may come from over the border.

"I think the South Australia Parliament will see this again," Mr McFetridge said.

"I won't know whether it will be before the next election. If the Victorians get it up, well who knows?"

Mr Weatherill defended Parliament's decision to push on with the debate through the night.

"The next sitting week we have a couple of people out of the Parliament on commitments, people that were supportive of the bill," he said.

"It seemed clear to me, to give the bill the best opportunity of success, we had to debate it.

"Speaking from myself, I'm saying I'm deeply saddened we weren't able to provide relief from abject suffering."

Voluntary euthanasia bills defeated 15 times in SA

Fourteen similar bills have been before the SA Parliament over recent years but failed.

Mr McFetridge's latest bill included some strong provisions.

Only someone with a terminal illness and found to be suffering unbearable pain that cannot be relieved through other measures could request voluntary euthanasia, and their decision must be endorsed by at least two doctors.

A previous bill, co-sponsored by Mr McFetridge and Labor's Steph Key, had faced criticism because it could have given a person who did not have a terminal illness access to euthanasia.

Two years ago, Max Bromson's family gathered in a motel room to watch him die after he secretly arranged to obtain the illegal euthanasia drug Nembutal from overseas.

His sister filmed the last stage of a fight that had dominated Max's final years, after he was diagnosed with terminal bone cancer in 2009.

She said they were probably motivated by legal concerns to capture his dying moments, as a way to show family members did not assist his death.

Last August, broadcaster and media personality Andrew Denton told the National Press Club there was a will in Australia for legally assisted voluntary suicide, but powerful people with vested interests were standing in the way of change.

Who voted in favour

Labor Liberal Independent Jay Weatherill Steven Marshall Geoff Brock Leon Bignell Vickie Chapman Paul Caica Duncan McFetridge Susan Close David Pisoni Nat Cook Isobel Redmond Annabel Digance Rachel Sanderson Jon Gee Corey Wingard Katrine Hildyard Eddie Hughes Steph Key Stephen Mullighan Lee Odenwalder Chris Picton Dana Wortley Frances Bedford

Who voted against