Malcolm Turnbull insists rolling out cashless debit cards across a third region is "an exercise in practical love" as his government expands the trial to the West Australian Goldfields.
A report into two trials in WA's East Kimberley and Ceduna in South Australia has shown a drop in problem drinking, drug and gambling abuse.
However, almost one-third of participants indicated the cards had made their lives worse, and only 17 per cent felt their children's lives had improved.
"This is an exercise in practical love, in compassion, in ensuring the taxpayers' dollars are not being spent on substance abuse and drugs leading to violence," the prime minister told reporters in Kalgoorlie on Friday.
"But above all, in ensuring that those families are spending their money where they should be spending it - on the food, clothing and necessities of life and making them better able to look after those kids."
There was nothing to indicate an improvement in crime across the first two trial sites, apart from fewer drug-driving offences and public intoxication.
The cards quarantine 80 per cent of welfare payments, which cannot be used to buy alcohol or gamble but can be used to pay for housing, food, clothing, household supplies and essentials.
The remaining 20 per cent of a welfare payment is placed in a person's regular bank account and can be withdrawn as cash.
Human Services Minister Alan Tudge says the government is rolling out the next trial at Kalgoorlie-Boulder because there is a demonstrable need in the community, particularly given the harm caused by drugs.
"This is an important measure, a difficult measure, but it can have a real impact on the ground at reducing some of the significant harms, particularly from alcohol and drugs," Mr Tudge said.
Greens community spokeswoman Rachel Siewert is disappointed about the announcement.
"I am concerned about the impacts this will have on people in the Goldfields community, particularly those on a working age-payment who are on a shoestring budget and cannot afford to have their income quarantined against their will," she said.
Opposition Leader Bill Shorten believes some people may benefit from the cards, but says it is important the scheme is embraced by the local community.
"What I don't want to see is genuine people who are down on their luck being treated with hard measures just to get a headline in the big cities," Mr Shorten told reporters in Torquay on Friday.
The government will soon announce a fourth trial site, with the minister indicating there was no reason it couldn't be rolled out across a metropolitan area.