Disability backlash over NDIS delay

Disability advocates are warning they will unleash a major campaign against the Abbott government if the national disability insurance scheme is delayed.

They have vowed to target key marginal seat Liberal MPs if people who have waited years to get care are forced to wait longer.

But the government is adamant there will be no slowing down of the multi-billion dollar scheme's full rollout, scheduled for completion by 2019.

Budget papers show $37 billion will be spent over four years to cover about 400,000 people eligible for care.

That makes the NDIS one of the most expensive single items of service in the federal budget - pushing up an already staggering welfare bill.

Assistant Social Services Minister Mitch Fifield said on Tuesday he was "absolutely" committed to delivering the scheme in full and "as soon as possible".

Responding to reports cabinet's razor gang has earmarked the scheme for consideration, Senator Fifield denied he was considering delaying tactics.

"We are not looking to cut the NDIS in any way, shape or form," he said, adding rollout negotiations with the states and territories were complex.

"We have to make sure that we get the rollout details right."

People With Disability Australia president Craig Wallace said the disability community was alarmed and concerned by a possible prolonging of the scheme.

"People have waited their whole lives for this kind of support - they aren't going to brook any kind of delay," he told AAP.

Mr Wallace warned of a "large-scale" backlash campaign, including targeted action in marginal seats, if there was any delay.

He said the government had pledged its bipartisan support for the scheme.

"This is the last remaining really big promise we can hold the government to."

The Australian Greens said it was important the government be held to account.

"I hope concerns expressed by the community stymie future discussions that could impact the NDIS and its rollout," Greens senator Rachel Siewert said in a statement.