A parliamentary committee says delays facing those trying to access services under the national disability insurance scheme are unacceptable.
Liberal MP and chair Kevin Andrews highlighted several issues noted in a report on the progress of the scheme between July 2016 and June this year.
Of "deep" concern was the fact the NDIS was running almost 20 per cent behind estimates for participants, particularly in the early childhood intervention cohort.
"As the scheme ramps up and substantially increases in complexity and size, the committee is concerned that quality in individualisation of plans may be compromised," he told parliament on Thursday.
On top of a fall in satisfaction ratings, the "litany" of issues raised by participants, providers, families and careers about their experience with the planning process is evidence of a downward trend, he said.
The committee accepted that some of the process and administration issues will be worked through and fixed in time.
But Mr Andrews said evidence received in recent public hearings suggested a culture was developing within the agency in charge "that is not placing the participant and those who support them at the centre of the scheme".
"People with disabilities should not be facing delays in accessing services under the NDIS, yet the time taken between an access requested is granted and planning meeting scheduled can be several months long," the former Abbott government minister said.
"The committee finds this is unacceptable."
It has made five recommendations, including that the agency gives participants a chance to view and review their plan before it is finalised.
Labor's social services spokeswoman Jenny Macklin endorsed Mr Andrews comments.
She said it was "heartbreaking" that people who campaigned so strongly for the NDIS are now expressing concerns.
"We should never ever forget the driving mission of the NDIS is to improve the lives of people with disability," she told MPs.
"The task for all of us is to ensure that that driving mission is achieved."