Indigenous academic Marcia Langton has declared cashless welfare card trials a "tragic failure" that have punished Centrelink recipients.

"They've let them down badly and now the system has been brought into disrepute by the viciousness of its implementation," she told the National Press Club.

Professor Langton said it was a tragedy the federal government departments responsible had not implemented the scheme in accordance with the commitments they made to indigenous leaders.

As part of the trial, the leaders recommended a committee of people living in the community make decisions about people who should be taken off the cashless welfare cards and receive their full income in cash.

They wanted to solve problems including alcohol-fuelled violence and child neglect in remote Aboriginal communities.

Local leaders in Kununurra in the East Kimberley wanted to take part in the trial and contributed to its design.

Professor Langton originally supported the trials but has since changed her mind, saying an essential part of the design was never implemented.

Professor Langton said the idea of the cards, along with other welfare reforms, was to wean people off social security and make them useful members of the economy.

"Not to savagely punish them," she said.

"Instead of sticking to the plan, minister after minister and bureaucrat after bureaucrat have wielded a big stick to punish the poor.

"It's pointless, and it's brutal, and I'm very disappointed."

The cashless welfare cards quarantine 80 per cent of Centrelink payments so the money can only be spent on essential items, rather than alcohol or gambling.

The cards are being trialled in Kununurra and the Goldfields in Western Australia, Ceduna in South Australia, and Hervey Bay in Queensland.

The federal government wants to extend these trials and introduce the cards into Cape York and the Northern Territory.

Draft laws to expand the scheme are before the lower house of federal parliament.