The Turnbull government denies it has plans to make changes to rules around eligibility for the national disability insurance scheme.
The federal government denies it is harbouring a secret plan to delay and water down the national disability insurance scheme.
The government has secured support from the states to expand the scheme's board, but rejects the move gives Canberra effective control.
A spokesman for Social Services Minister Christian Porter told AAP on Monday the government had no plans to change eligibility rules.
It also remained committed to funding the scheme and delivering it within budget.
"Given the complexity of this reform and the significant level of funding being invested, governments will continue to closely monitor scheme governance and scheme costs to ensure every dollar used is invested as efficiently and effectively as possible," he said.
Opposition disability spokeswoman Jenny Macklin accused the government of having a secret plan to take control of the scheme.
"This is a transparent attempt by Christian Porter to ignore the needs of people with disability, sideline the states and territories, sack the board members and put in his own cronies who will take orders from him," she said. "It wants the power to cut the scheme, change the eligibility of participants and delay its implementation."
Victoria's Disability Minister Martin Foley accused the government of walking away from a national consensus on the NDIS in an attempt to shift its budget problems onto Australians with disabilities.
It was trying to control how the NDIS board was appointed so it became an arm of government rather than an independent skills-based board.
"It's walking away from what has been a 20-year battle by people with disabilities," he told ABC radio.
Business leaders warn the scheme faces cost blowouts of $3 billion a year.
Tony Shepherd, who led the Abbott government's commission of audit, says senior government members are concerned the final cost of the scheme will be closer to $25 billion rather than $22 billion.
"There is no budget control over the number of people who qualify and the size of the packages of support and the commonwealth largely takes on that risk, so in effect they have signed a blank cheque," he told The Australian.
Business Council of Australia chief Jennifer Westacott said governments should not stop the rollout.
"(But) they should also not be afraid to acknowledge where risks in the scheme are materialising and go back to the first principles of design set out by the Productivity Commission and, if necessary change course and redesign," she writes in the paper.
People with Disability Australia president Craig Wallace said commentary, such as the BCA's, worried people.
"For something where you've got all of the boxes being ticked on good governance, transparency and cost, why is there this kind of blizzard of misinformed commentary? Is it the BCA once again searching for relevance?" he told Sky News.
It was time for the government to commit to funding the scheme in perpetuity, he said.
Mr Porter's spokesman said further discussions will take place at the next COAG meeting.
Disability Australia spokesman Matthew Wright said Mr Shepherd should cease his "scaremongering", for the sake of hundreds of thousands of people with a disability and their families.
It was also critical the board was independent.
Disability Australia supported the current system of state-nominated representatives in consultation with the Commonwealth, he said. Claims of a cost blow-out were untruthful and unhelpful.