The federal government will leave it to the agency responsible for the national disability scheme to recommend any change to the rollout timetable.
An independent capability review of the NDIS Agency says a realistic reassessment of plans to include 300,000 people in the landmark scheme from 2017 needs to be done sooner rather than later.
There are fears within the disability sector the government will use the review to extend the seven-year rollout.
Assistant Social Services Minister Mitch Fifield insists the timetable is subject to inter-government agreements between the commonwealth and states and territories.
"There can't be a change to that timeframe without negotiation and agreement of all jurisdictions," he told The Pulse radio in Geelong on Friday.
However, the NDIS Agency would provide the government with advice about its ability to meet the timetable.
"The most important thing is to have an honest assessment of the capability of the agency."
John Della Bosca, director of the Every Australian Counts campaign, concedes the scheme's rollout is a big job.
"But it's hardly sending someone to the moon and it should not take a decade to deliver," he told ABC Radio.
The peak body for non-government services in the sector, National Disability Services, says the scheme is eight months into a six-year marathon.
"We've exerted a lot of effort and ingenuity to get this far so quickly - it's too early to decide that the road ahead is too steep," chief executive Ken Baker said.
Federal Labor says it will be "absolutely disastrous" for people with disabilities if the rollout is pushed back.
"Let's just fix whatever problems exist and get on with making sure people with disability get the support they need," disability reform spokeswoman Jenny Macklin said.
