The parents of two boys with disabilities say they were shocked with how the NDIS responded to their request for funding for basic equipment.

Hobart couple Michael and Jasna Baric are full-time carers for their sons Joshua and Lucas, who have Duchenne Muscular Dystrophy.

The condition means the boys' muscles are progressively degenerating and becoming weaker.

"The disease is degenerative; it won't get any better," Ms Baric said.

'They'll physically lose their ability to walk and use their body.

"While you're watching other kids grow and develop and playing sport, we're watching ours go the other way," Michael Baric said.

In February, the Barics applied through the National Disability Insurance Scheme (NDIS) for money to buy their 11-year-old son Joshua a mobility scooter, an adjustable bed and a reclining chair.

They waited three months for a response and were shocked by the "very cold" reply they eventually received.

The email from the NDIS queried the value of investing in an adult-sized adjustable bed for 11-year-old Joshua, saying "it seems it would be unlikely he will need a bed of this height for a very long time, if at all."

The email also suggested cheaper alternatives to a recliner, like a chair with arm rests or alternative supports including "leg raisers on the family's existing lounge suite".

"They wanted me to look for some blocks of wood to stick under the couch so that my son had easier access to get on and off it," Mr Baric said.

"I just thought to myself, Oh my God.

"I didn't realise we'd have to walk over 10 kilometres of broken glass just to try and get a couple of things to help."

'Hundreds are having difficulties with NDIS'

Michael and Jasna Baric are considering taking legal action over their NDIS issues. ( ABC News: Gregor Salmon )

While struggling to secure funding for equipment, the Barics have also found it hard to spend NDIS money on speech and other therapies for their children, both of whom also have autism.

"There's a huge waiting list for the boys to seek professional help at that level,'' Mr Baric said.

According to independent MP Andrew Wilkie, this is a common story.

"I would suggest that in Tasmania there are hundreds who are having difficulties. Across the country, there are thousands," he said.

"They are finding the NDIS a bureaucratic maze that is just too difficult to navigate.

"Last year, the NDIS spent about $10 million fighting legal battles in the courts, people challenging decisions by the NDIS and the NDIS has lost almost of the cases that have been brought against it."

Funding has been approved: NDIS

Minutes after this story was published, NDIS administrators emailed the ABC to say some of the Barics' funding had been approved.

"On 17 May 2018, the decision was made to approve funding in Joshua's plan, including funding for the adjustable bed, scooter and options in relation to the request for the raiser chair," a spokesperson said.

"The NDIA have contacted Joshua’s family, confirming that funding has been approved.

"In October 2017, the NDIA [National Disability Insurance Agency] released details of the new 'pathway' designed to significantly improve the experience people and organisations have with the ground-breaking NDIS from their first interaction to their ongoing engagement with the scheme."

'They fast-tracked it to cover themselves'

But Mr Baric said he had not been contacted by the NDIA with the news of Joshua's funding approval until after the ABC received the NDIA email.

He said the speed with which the funding was approved, with no follow-up questions relating to the items they wanted to buy for Joshua, was to do with the fact that he had shared his story with the ABC.

"Obviously, they've fast-tracked it to cover themselves," he said.

"I said I was going to the ABC and I think because of that threat they've fast-tracked it — that's all this is.

"There's no way it would have been addressed this quickly if I hadn't have contacted the ABC."

Mr Baric said he will now be interested to see how long it takes to get funding for Lucas.