PRIME Minister Malcolm Turnbull will stare down welfare advocates critical of the government's plan to drug test some new dole recipients, labelling an attack on the budget proposal "disappointing".

"Really, what is more important in the welfare area than getting people back into a job," Mr Turnbull said this morning.

"If people are on welfare and they have got an addiction problem, then that needs to be identified and helped.

"They need to get off the addiction so they can get back into the workforce, this is helping people."

The Greens said they would seek advice on whether the move, only planned to be a trial of around 5000 at this early stage, was legal.

Under the plan, being drunk or drug-affected will not be accepted as an excuse for repeat offenders for failing to meet mutual obligations like work-for-the-dole appointments or job interviews.

Greens leader Richard Di Natale last night said it was a "deprivation of liberty" and suggested it could be extended by the government to Medicare recipients.

South Australian Independent Senator Nick Xenophon speaks at the Council of Small Business of Australia's (COSBOA) National Small Business Summit in Brisbane, Friday, July 8, 2016. The Nick Xenophon Team is likely to have won two lower house seats and three in the Senate. With the likelihood of a hung parliament, based on Australian Electoral Commission data, both Australian Prime Minister Malcolm Turnbull and Australian Opposition leader Bill Shorten are now in a race to shore up crossbench support to form minority government in the Australian Parliament. (AAP Image/Dan Peled) NO ARCHIVING
South Australian Independent Nick Xenophon DAN PELED

Nick Xenophon also has concerns about the measure, but it is being backed by fellow crossbencher Jacqui Lambie.

Labor's treasury spokesman Chris Bowen said he was open to supporting the measure, part of a suite of welfare reforms including a demerit point system to raise $632 million first revealed by The Daily Telegraph yesterday.

"Of course we don't want to see anybody taking illegal drugs, welfare recipient or not welfare recipient, but by the same token what we can't do in Australia is create an underclass of people just taken off all support and thrown on the street," Mr Bowen said.

"That has implications for everybody, implications for everybody not just those affected so this is a measure which will take some careful consideration.

"We have some important decisions to make there."

Treasurer Scott Morrison, who unveiled the new measures last night, said the government would consider the results of the drug testing trials.

"We are going to see if this will actually help, whether it will work," he said.

"If people are pinged on one occasion then they can be referred to treatment.

"But if there is no response, if you can just not turn up to job interviews, not do your mutual obligation requirements, not meet with your job service provider, not take a job that's been offered to you which is reasonable work and your excuse is, 'Well, I was too drunk, or drugged', that's not fair to taxpayers, and it's actually not fair to them either.

"We should actually step in, and that's what this does."