Senior officials of the National Disability Insurance Agency (NDIA) have been grilled by a Senate Estimates committee over the case of a young Tasmanian man who died waiting for vital equipment.

The family of Tim Rubenach from Gray in north-east Tasmania spoke out against the scheme on Thursday after the 32-year-old's death a week ago from pneumonia.

Mr Rubenach suffered from severe epilepsy and was unable to talk.

His family said he waited desperately and in pain for a special bed and motorised wheelchair promised by the scheme, but they never came before he died.

The case prompted federal independent MP Andrew Wilkie to call for a complete independent overhaul of the NDIS, saying he would be inundated by complaints on an almost-daily basis from Tasmanians who have encountered a "bureaucratic brick wall".

In an often tense Senate Estimates question and answer session, several senators expressed incredulity about the apparent disconnect between the NDIA bureaucracy and families in dire need.

"Are you saying at your level you do not have a system to make sure that, on a case-by-case basis, people aren't missing out on what they need?" asked Tasmanian Labor senator Carol Brown.

Fellow Labor senator Murray Watt of WA also demanded answers, asking: "Who is actually pushing the local area coordinators to make sure that the recipients are actually getting what's in their plan?

"If this system is so perfect … why is this happening?, Senator Watt asked.

"What's the biggest change that needs to happen to be made to this system of accountability to stop this happening?"

Officials apologise

The exchange prompted senior NDIA officials Robert De Luca and Vicki Rundle to apologise for Mr Rubenach's delays and acknowledge his equipment did not "arrive on time".

Tim Rubenach, pictured on his last birthday. ( Supplied: Hannah Rubenach-Quinn )

Mr De Luca said he had only become aware of the case in the media and was unsure whether the family had been contacted by agency representatives.

"We are seeking to roll this system out. As we go we will discover areas where we can improve interfaces and engagements," Mr De Luca said.

Fellow agency official Michael Francis told Senator Watt there was "probably two elements" in answering his questions.

"The first is that we have partners in the community branch who are responsible for maintaining that relationship, contract management, monitoring the performance of those respective partners and the services that they provide," Mr Francis said.

"So there will be KPIs within those contracts or agreements that we have with those particular partners in the community," he said.

Advocate anger

The response by the officials drew an angry reaction from WA Greens senator and disability advocate Jordan Steele-John.

Senator Steele-John — who uses a wheelchair — described the Rubenach's ordeal as a "prolonged crisis" at the hands of the NDIS.

"A man is dead. A family is grieving the loss of a son," he said.

"Regardless of the various contextual factors around that case, you could not have written a more obvious cry for help if they had written 'help me' in the letters they have sent us and the letters they have sent the NDIA and the letters they have sent the Minister."

"Speaking very frankly, they would not give a shit whether anyone in this room is particularly sorry about the death of their son.

They would want to know that the agency owns the failure that is represented in the death of their son, as does the Government who currently presides over it."

"Disabled folk in this country have been dying in the hands of poorly delivered services for hundreds of years," Senator Steele-John said.

"It's nothing new."

"The point of the NDIS was this was not to happen any more."

Beverley and Peter Rubenach have sworn to continue their fight over their son Tim's treatment to help other NDIS patients. ( ABC News: Laura Beavis )

A spokeswoman for the Commonwealth's Department of Social Services, Cathryn Campbell, said the agency was looking into Tim Rubenach's death, which she described as "a very sad case" and acknowledged there were "broader systemic issues".

On Thursday, Tim's mother Beverley Rubenach spoke of the family's heartbreak and told the ABC the family had wanted to take him to the beach one last time, but was unable to without the promised wheelchair.

"He used to remember the days when he could run along the beach with his dog. And it got to the point where we couldn't support him even with two people walking him to the beach," Ms Rubenach said.

"So the all-terrain wheelchair was his freedom. He knew that he could get out and be a little bit independent."