The Turnbull government has delivered a thinly-veiled threat to opponents of its proposed welfare cuts.
Carve away at the savings measures as much as you like, but know you'll be tearing money from the pockets Australians with disabilities, Treasurer Scott Morrison has warned.
About $3 billion in welfare cuts will be funnelled into a designated kitty for the national disability insurance scheme, quarantining about $5 billion for the scheme by the end of 2020.
"This is saying that there is a locked box over in social services ... the money that will come from making these changes will go to ensure that the NDIS continues to be funded and delivered on an ongoing basis," Mr Morrison told reporters in Canberra on Monday.
"Anything not passed through this bill means that the NDIS special account will be the poorer for it and will have to be made up from other sources."
Social Services Minister Christian Porter conceded it was possible not all of the 16 cuts in the "omnibus" welfare bill would clear parliament.
"We are going to take the case right up until the bill is passed," he said.
"The time that you truly know whether you will get support on each and every measure is the time that the vote is taken. If we make savings in those areas, they will go on to pay for the NDIS."
The $5.5 billion in savings from the welfare overhaul was to be split between extra childcare spending - about $1.6 billion - with the rest tipped into balancing the budget.
But Mr Morrison said debiting the savings into the NDIS special account would deliver "greater certainty" around the delivery of the scheme.
Mr Morrison told reporters there would be no impact on the budget's cash balances as a result of the decision.
"It goes to budget repair. It is going to offset big spending of the government," he said.
Among the savings measures are phasing out annual Family Tax Benefit supplements in favour of increased fortnightly payments, ending carbon tax compensation for new welfare recipients, making young jobseekers wait a month before receiving income support, and forcing under-25s off the dole and onto the lower youth allowance.
The government informed Senate crossbenchers, Labor and the Greens about its new plans for the rest of those savings on Monday.
Labor social services spokeswoman Jenny Macklin said the government was holding the NDIS hostage in a disgraceful political game of brinksmanship.
"People with a disability do not deserve to be treated with such contempt by the Turnbull government," she said.
"Linking the delivery of the NDIS to massive cuts to families, pensioners, people with disability, carers and Newstart recipients is simply appalling."
Greens senator Rachel Siewert said slashing welfare measures to fund the NDIS was akin to robbing Peter to pay Paul, accusing the treasurer of attempting a "cheap trick" to pile pressure on the Senate.