Labor challenges Turnbull on welfare bill

The federal opposition has asked Prime Minister Malcolm Turnbull to explain why welfare cuts are needed to fund child care.

Malcolm Turnbull has rejected Labor claims the government's revised plan for welfare savings will hurt families.

The coalition on Wednesday set aside an omnibus bill with controversial cuts to family benefits and other welfare spending for separate bills which are expected to receive Senate crossbench support and pass by the end of the week.

Labor leader Bill Shorten asked the prime minister in parliament why 1.5 million families would have their payments cut in order to pay for child care.

"Why is the prime minister pitting families against each other, robbing Peter to pay Paul and leaving 1.5 million families worse off?" he asked.

Mr Turnbull said the coalition had taken its plan to an election, which it won.

"We know it supports the families that need help the most," Mr Turnbull told parliament on Wednesday.

"(The former Labor families minister) used to say social welfare reforms have to be paid for. Not anymore. Apparently you just run up more debt."