She says she won't vote for the coalition government's plan until she sees thousands of drug rehabilitation beds in place around Australia.

On a separate issue, Senator Lambie also says she will tour trial sites for the cashless welfare card over the next six months to decide if she will support a government plan to extend it to other areas.

The federal government wants to expand cashless welfare card trials and drug test thousands of Newstart and Youth Allowance recipients.

Senator Lambie initially indicated she would "absolutely" support the drug testing trials if federal politicians were also screened for illicit substances.

But the Tasmanian senator has since reshaped her demands.

"You show me when the buildings go up, you show me when the beds go in there, then we'll discuss it," she told ABC News on Monday.

"We're not voting for this bill because I already know the services are not there."

Centre Alliance senator Rex Patrick said his party did not support the drug testing because evidence from overseas showed it did not work.

"At this point in time things haven't changed from when we didn't support it in the 45th parliament," he told Sky News.

The legislation includes a $10 million "treatment fund" to boost rehabilitation services across the trial sites.

"I am really puzzled by the level of opposition to the government trying to tackle a problem of drug addiction for people who aren't in work," Prime Minister Scott Morrison told The 7:30 Report.

"(We're) helping them get over it with referral to proper services and funding those services in those trial areas and if that works, well, that gives us the opportunity to take that out more broadly that."

Mr Morrison also insisted the trials of the cashless welfare card had seen improvements in youth unemployment, and participants were embracing it.

The coalition will bring the drug-testing bill through the lower house in the next fortnight, before taking it to the Senate at the earliest opportunity after that.

The Australian Council of Social Service is urging parliament to reject the "demeaning, expensive" drug-testing plan and the expansion of the "impractical" cashless welfare card.

Cashless welfare cards, which quarantine 80 per cent of payments so they can only be spent on essentials, are currently in use across four trial sites in South Australia, Western Australia and Queensland.

Deputy opposition leader Richard Marles confirmed Labor remained opposed to a nationwide rollout.

"The auditor-general has been scathing about the effectiveness of this where it has been tried. The evidence that the government cites is really skinny," he told the ABC.

Nationals backbencher Barnaby Joyce has no qualms about MPs being drug tested.

"I don't think you should vote if you're wired."

The two-year drug testing trial would be rolled out in three locations - Logan in Queensland, Canterbury-Bankstown in NSW and Mandurah in WA.

Australian Associated Press