A client found themselves $8000 in debt due to poor management and others were left languishing in hospital for more than a year without accessible housing.

These are some of the stories detailed by advocacy groups, carers and service providers in submissions to an ACT parliamentary inquiry into the NDIS, starting on Friday.

While almost all submissions stated their support for the reform, which aims to improve choices and services for people living with disability, most also described soul-crushing delays in an increasingly opaque bureaucracy. Others alleged incompetence, even "intimidation" at the hands of the National Disability Insurance Agency, which manages the scheme.

The ACT Human Rights Commission accused the agency of cutting it out of the complaints resolution process, while the territory's peak advocacy group for people with disabilities labelled the scheme as "traumatic".

Concerns highlighted across the 70 submissions include:

"There have been times when I felt so stressed over the NDIS I wanted nothing more to do with it," one participant said.

Another said they had less access than before "because no one will repair or replace the [equipment I use] so I have been stuck in my house since it broke 14 months ago unless I struggle to walk with great pain for important medical appointments".

The ACT Disability, Aged and Carer Advocacy Service had been flooded with so many NDIS clients needing help, it said it could no longer keep up with demand - and was often unable to offer advocacy on other matters such as discrimination and employment.

Last financial year, chief executive Fiona May said the service had turned away half of those who asked for help, instead setting up a special team delivering "limited support over the phone".

"We’re having to triage the cases that come to us, with this level of demand [they] have to be at immediate risk of significant harm such as homelessness or institutionalisation," Ms May said.

"This year, we think that data will show even more unmet demand. It's very concerning."

The ACT Human Rights Commission also sounded the alarm over unclear pathways for complaints and appeals within the scheme.

"The NDIA has consistently refused to engage with the ACT HRC in the exercise of its lawful complaint investigation functions," its submission said.

While ADACAS was currently supporting about 30 NDIS clients in the ACT Administrative Appeals Tribunal, the commission said this process was costly, slow and not available to everyone, while it was well placed to offer an informal alternative.

ACT Public Advocate Jodie Griffiths-Cook said many people were benefiting from the scheme, but others were losing out due to a lack of resources.

"It's an equity issue. The burden of responsibility should not rest solely on people with a disability to keep fighting and fighting for the things they're entitled to," Ms Griffiths-Cook said.

"We need to ensure people are informed and empowered to create the change they need to see in their lives."

ACT Minister for Disability Rachel Stephen-Smith said the government had heard a "significant amount" of concerns from local NDIS participants and would consider any recommendations made by the inquiry.

"As the first jurisdiction to fully transition to the NDIS, it is important that the experiences and lessons from ACT are acted upon and inform the national roll-out," Ms Stephen-Smith said.

Chair of the committee ACT backbencher Chris Steel said he hoped the inquiry would improve understanding and recommend improvements to the scheme both for the NDIA and the ACT government.

An improved NDIS pathways program with more face-to-face consultation is being trialled in Victoria.

The NDIA has been contacted for comment.