The cashless welfare card has been trialled in three sites across Australia and the government has flagged it intends to roll it out more broadly.

For welfare recipients on the card, 80 per cent of their payment is quarantined on the card, which then can't be used at bottle shops or gambling venues. Just 20 per cent is left in cash, a move which is designed to reduce alcohol, drugs and gambling issues.

People on the card were last year given the opportunity to apply to be exempt from the card, and despite 635 applications, no one has yet been able to opt out.

Under questioning from Greens Senator Rachel Siewert, Social Services Minister Anne Ruston said no one had been denied exit from the card, but that assessing applications was complex.

"There was a number of quite complex pieces of information that were required, some of which were actually under the purview of the state and territory governments," Senator Ruston said in Senate question time.

"The process is ongoing, people who have made application will be assessed on a case by case basis. And obviously processing times are going to vary between applications."

Senator Ruston wouldn't concede that people hadn't been able to exit the card because it was too hard and couldn't say when she expected people would be successful in their applications to be removed from the card.

People who want to opt-out of the card have to prove "reasonable and responsible management of their affairs generally, including financial affairs".

A person's criminal record and risk of homelessness are part of the consideration for whether a person is managing their affairs.

The card has been criticised from Labor, the Greens and welfare advocates, who argue it is discriminatory as it has so far been rolled out in majority Aboriginal communities. People on the card have also said it makes it harder to buy second hand goods or from op shops, meaning it's harder to get by on the Newstart payment, which hasn't increased in 24 years.