An alliance of 20 disability representatives, providers and advocates are on Thursday urging federal politicians to stop independent assessments.

The groups say the assessments undermine the integrity of the National Disability Insurance Scheme.

Flagged changes would see independent assessments occur for new participants and plan reviews, to determine what type of support people need.

The free assessments are done by healthcare professionals who do not know a participant, rather than their doctor of choice.

NDIS Minister Stuart Robert wants to cement the change into law mid-year.

Independent assessments will make the scheme "better and fairer", a spokesman for the minister says.

"Access to the NDIS should not be based on how much someone can pay for a report," he said.

Mr Robert has taken to releasing data from the NDIS showing plans are more expensive in some federal electorates compared to others, without providing any further analysis on why.

He wants plans to be more consistent, while Inclusion Australia chief Catherine McAlpine says the changes will fundamentally alter the individualised nature of the NDIS.

"This is not the NDIS we fought for," she said.

"People with disabilities must be treated as individuals, not numbers."

Aaron participated in a pilot for the independent assessments and had a physiotherapist tasked with deciding the support needed for his autism.

His occupational therapist and psychologist were not consulted.

"The assessment conducted was not thorough, not in context, and not done by a suitable professional," Aaron said.

"It did not reflect my life or what my needs are."

The assessment mainly consists of 'yes' or 'no' questions which the organisations fear does not allow added context or complexities to be taken into account.

There will be no way for participants to appeal decisions.

The group includes the Australian Autism Alliance, Deaf Australia, Brain Injury Australia and Down Syndrome Australia.

They held an online briefing to politicians on Thursday explaining why the changes should not go ahead.

A handful of Labor MPs, independents Zali Steggall and Rebekha Sharkie, as well as Greens disability spokesman Senator Jordon Steele-John took part in the briefing.

A review of the scheme recommended independent assessments for new - not existing - participants, contrary to the government's framing.

Labor's NDIS spokesman Bill Shorten said the change had been sprung on participants, with most opposing it.

"Stuart Robert needs to put the emergency brakes on this offensive and dangerous plan to make 400,000 people re-audition in front of strangers to retain NDIS coverage."

Australian Associated Press