Welfare drug test trial passes lower house

The federal government concedes it will need to try something else if a trial to drug test welfare recipients does not work.

The proposal, part of a broad package of reforms to the welfare system, passed parliament's lower house on Monday despite opposition from Labor.

Several changes were made to the original legislation, including the plan to drug test 5000 new jobseekers in three different locations from January.

Greater support will be given to those who have part of their income quarantined if the regime poses a serious risk to their mental, physical or emotional wellbeing, Social Services Minister Christian Porter told parliament.

He said the pilot program is designed to see whether the welfare system can be effectively used to compel people into treatment.

"If it does not work of course there'll be a need to try something else, if it does work we will have improved the lives of people with those drug problems," he said.

He argued the entire package of changes were critical to ensuring Australia's welfare system was efficient, effective and sustainable.

Labor and the Greens are flatly opposed, so the government must court support from the Senate crossbench.

Mr Porter noted some concerns from crossbench MP Rebekha Sharkie from the Nick Xenophon Team, whose bloc of three votes in the upper house is crucial.

Nick Xenophon has given conditional support to the bill, saying last month he wants to work constructively with government to help people off drugs.