A trial of cashless welfare cards across Western Australia and South Australia has officially been extended for a year, while Cape York will also get the controversial program.
Laws put forward by the government cleared federal parliament on Thursday, with Labor's backing.
Opposition human services spokeswoman Linda Burney says amendments made by Labor have improved the legislation.
"Labor's amendments will mitigate the arbitrary impacts that this card will have on welfare participants," she told the lower house.
But the party remains concerned about the card and its rollout.
"There simply is no evidence that this card works and the government has botched its own assessment of the card," Ms Burney said.
Social Services Minister Paul Fletcher says the card is making a real difference to the lives of thousands of Australians.
Extending the trial will help the government keep testing its effectiveness, he said, with a second evaluation now underway.
Greens Senator Rachel Siewert earlier said the card "flies in the face of self-determination".
She rejected suggestions Labor was in a tough spot and needed to extend the trials to provide people with certainty.
