Paralympian Kurt Fearnley is leading the charge for furious disability rights advocates angry at the Turnbull government's decision to abandon a Medicare levy hike to pay for the National Disability Insurance Scheme.
The groups, now anxious about the future of the NDIS, are demanding a secure, long-term funding source.
"We continue to play politics and kick the can down the road (in terms of securing stable funding). This move will not go quietly," Mr Fearnley said on Thursday.
People with Disability Australia co-chief executive Therese Sands said her members felt "stunned, betrayed and ambushed" after the key 2017 federal budget measure was dropped.
"The Medicare levy increase was intended to guarantee funding for the NDIS in the long term," Ms Sands said.
"We are now left to go cap-in-hand, like charity cases, at each and every budget. This is unacceptable."
Treasurer Scott Morrison said increasing the Medicare levy by 0.5 per cent to 2.5 per cent to raise $88 billion was no longer needed, thanks to better-than-expected government revenue.
His pre-budget backflip will be welcomed by taxpayers who will save hundreds of dollars each year.
Shadow treasurer Chris Bowen also confirmed the opposition will not purse a Medicare levy rise for those on incomes above $87,000 - the only limit it had been willing to accept.
"They've now dropped the entire policy so obviously the effort to compromise is now null and void as well," Mr Bowen told reporters in Sydney.
Mr Morrison said tax receipts up until February are expected to have run $4.8 billion higher than estimated in December and therefore the increase isn't needed. But he insisted the government remained absolutely committed to the NDIS.
"We will fully, absolutely, look you in the eye and say that funding for NDIS is there and you'll see that in the budget," the treasurer told ABC radio.
"It's guaranteed because of the stronger economy we are delivering."
But Cassandra Goldie, from the Australian Council of Social Service, said the decision reinforced growing concerns about the quality and certainty of services people received from the NDIS.
"Everyone who can afford to do so should contribute to essential services like the NDIS, and securing the revenue to guarantee essential services should be a bipartisan commitment," Dr Goldie said.
Disability Discrimination Commissioner Alastair McEwin wasn't concerned about where funding for the scheme came from, so long as it was guaranteed.
Australian Medical Association President Michael Gannon was also agnostic about the NDIS funding source.
Australian Associated Press