Malcolm Turnbull has challenged Labor to support a new childcare package as the government made last-minute changes to the way it will be funded to get crossbench support.
Labor says the government is recycling cuts from the 2014 Abbott government budget in order to raise the $1.6 billion to pay for the new scheme, just weeks ahead of the 2017 budget.
But the prime minister told parliament Labor had no plan to pay for childcare fee relief or addressing other pressures on the cost of living.
"A family earning less than $65,000 a year would only pay around $15 (a day) for childcare," Mr Turnbull said of the scheme, which is expected to pass parliament by the week's end.
"And a family earning $50,000 a year with two children in daycare would be more than $3000 a year better off. You'd think Labor would support that."
The government is aiming to pass its revised welfare savings bill before putting the separate childcare bill to a vote in the Senate, which has extended its hours to Friday if necessary to deal with them.
Mr Shorten told parliament even the revised welfare savings were unpalatable.
"Labor has fought these cuts every day since then, defending pensioners and families - when will the prime minister stop recycling cuts from the 2014 budget and stop hurting families?" he said.
An Essential poll released on Tuesday gave Labor a 55-45 per cent two-party lead over the coalition, with 61 per cent of voters saying Labor "looks after the interests of working people" (compared with 30 per cent saying the same of the Liberal Party).
Treasurer Scott Morrison described Labor's opposition as "desperate populism".
"When it comes to economic policy the leader of the opposition is just a sucking vacuum," Mr Morrison said.
The government had combined a $1.6 billion boost to childcare and $5.6 billion in welfare cuts in a single omnibus savings bill, but on Wednesday chose to split it and drop a number of cuts after acknowledging certain defeat in the Senate.
Opposition childcare spokeswoman Kate Ellis said Labor backed childcare reform and better assistance for families, but wants to ensure the most vulnerable children are supported.
The main welfare change announced on Wednesday was freezing family tax benefit rates for two years saving almost $1.4 billion.
Finance Minister Mathias Cormann said no family receiving payments today would lose payments.
The debate came as former Liberal senator Cory Bernardi, who has formed his own Australian Conservatives party, claimed victory on changes to racial discrimination laws.
"It's amazing what a bit of leadership tension does for intestinal fortitude," Senator Bernardi said.
Cabinet minister Arthur Sinodinos denied Mr Turnbull was under pressure.
"I think his leadership is actually quite secure - and I think that the honesty he's shown in tackling some difficult issues since he got the job has been fantastic to watch," Senator Sinodinos said.
Some coalition members voiced concerns in the party room on Tuesday that the government was putting secondary issues such as free speech ahead of jobs and the rising cost of living.
