Labor leader Bill Shorten has vowed to protect the funding of the National Insurance Disability Scheme if he wins the 18 May election.
Mr Shorten says Labor will create an NDIS future fund to guarantee that every dollar budgeted for the scheme will go towards it.
"Labor's NDIS future fund will be a locked box - a budgeted guarantee to Australians with a disability that the NDIS will be properly and fully funded," he said on Friday.
"This year's budget projects an underspend on the NDIS of $1.6 billion because of the Liberals' delays and caps."
Mr Shorten will make the announcement in Melbourne, where he has returned after spending Thursday in Tasmania.
The opposition leader campaigned in the Labor-held seats of Lyons and Braddon, making a $75 million pledge for thousands of jobs in the renewable energy sector.
Mr Shorten still faces questions over the cost of his 45 per cent emissions reduction target.
He says any costs are an investment for the future.
Labor has rejected new modelling which shows the target could slow economic growth by up to 0.8 per cent over a decade, or less if more international permits are allowed.
"We will file this report under 'P' for propaganda. It's full of wrong assumptions," Mr Shorten told reporters in Burnie.
But the Labor leader will face pressure over the costs from Prime Minister Scott Morrison on Friday night when the pair go head to head for the second leaders' debate.
Scott Morrison and Bill Shorten line up for the second debate in Brisbane on Friday night. Source: AAP
The Sky News-Courier Mail people's forum will be held in Brisbane with 100 undecided voters.
Mr Shorten was declared the winner of the first debate, which was held in Perth on Monday night.
He was picked as the winner over Mr Morrison despite not being able to provide figures related to the cost of his climate policy.
It's an issue that will continue to snap at Mr Shorten until Australians head to the polls, despite his argument that it will cost more in the long run if the nation doesn't act on climate change.
"The reality is the single greatest reason why energy prices have gone up in Australia is there's just a lack of energy policy," he said.
