Andrew Johnson was diagnosed with profound autism when he was four and went into a Department of Human Services-managed group home when he was 13.

The 30-year-old cannot speak, has autism, Tourette syndrome, bipolar disorder, attention deficit hyperactivity disorder, obsessive compulsive disorder, epilepsy, and needs a stomach tube to help him feed.

His mother, Deb Johnson, said she felt "physically sick" after receiving a letter from Centrelink on September 15 demanding evidence that her son was entitled to the pension.

She was given just two weeks to collate the paperwork, which included decades-old documents.

Mrs Johnson was finally granted an extension, but was then told to start preparing for a review for her elder son, William, 32, who has been in state care since 1999, and suffers from profound autism.

She was also told Andrew would be required to undergo an IQ test.

But on Thursday, the mother-of-four suddenly received a call from Centrelink saying no further action would be required, citing a letter from Andrew's gastroenterologist as the reason behind the decision.

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Human Services Minister Alan Tudge – who stepped in following questions from Fairfax Media – said Andrew would continue to receive his disability pension.

"We will not be asking him to look for work because he has met the specific criteria for manifest eligibility," Mr Tudge said.

"Once the department can confirm a person meets the specific criteria for manifest eligibility for DSP, they will not need to complete another review again in future."

While Mrs Johnson was happy with the eventual outcome, she was less than pleased with the process.

"They have put me through absolute hell," she said.

"I have been really severely stressed. I have been to four appointments in a week, three specialists and one GP."

"I can't believe they have accepted just a gastroenterologist's report and say it covers all disabilities, when they have asked us to jump through hoops with [documents showing] onset of symptoms, dates of diagnosis, and an IQ test," she said.

"They haven't got one report from me that I have collected in the [past] week-and-a-half. After all of this running around and being out of pocket ... it's just not fair to put families through it."

Federal MP for Bruce, Julian Hill, who wrote to the Human Services Minister on behalf of the Johnson family, said the review was "more than a little ridiculous".

"The reprieve for the family is welcome and overdue, it should have never have got to this," Mr Hill said.

"And it raises more questions than it answers. What's the basis of these kind of nonsensical reviews, and how many reviews are being similarly conducted? The cost to Deb, to Medicare to prove the bleeding obvious has to be factored."

A Human Services Department spokeswoman said William would not be subjected to a review because the department had the information they needed for him to continue to receive his payment.

She said the target group for the reviews were current disability support pension recipients who had not been reviewed in the past two years. Those living in state-based assisted living, the spokeswoman said, were not automatically granted a pension.

In his letter to Centrelink, Andrew's consultant neurologist, who wished to remain anonymous, called the review a waste of time and "traumatic exercise for the families".

"I have no idea what managers in Centrelink were thinking when they initiated this process," he wrote.

"There is no question in my mind that he is not in a position to work and needs ongoing, long-term community support and will need to stay on a disability support pension until he dies."

The government is reviewing 90,000 disability support recipients for their ability to work after welfare changes in the 2016 federal budget, with 30,000 undergoing medical assessment.​

Opposition human services spokeswoman Linda Burney said a welfare target crackdown should not target those most at risk.

"Minister Tudge should direct his department to use some common sense," Ms Burney said.

"If a person with disability is living in state care, I find it hard to believe that there isn't another, more cost-effective and less cruel way to assess their eligibility for support payments."