Mandy Hunwick used to love going to work, but then it all became too stressful.

Her vision became blurry, she couldn't remember simple tasks and became increasingly fatigued.

Key points: About 200,000 people with a disability are receiving Newstart payments

Many would have previously qualified for the Disability Support Pension (DSP), which is $370 a fortnight more

The success rate for DSP applications has plunged since the introduction of impairment tables

The 42-year-old was eventually diagnosed with Multiple Sclerosis (MS), along with auto-immune arthritis and vasculitis, a disease that restricts blood flow.

Ms Hunwick was forced to leave her job at a Queensland government department and applied for the Disability Support Pension (DSP).

"I thought that it was going to be a short, easy process," she said.

"It took 17 months. And I had to fight for it. I literally went through hell just trying to get it. And it caused me to almost want to kill myself," she said.

She applied for the DSP in January 2018, providing Centrelink with statements from doctors and occupational therapists.

Eight months later, she was rejected. She applied for a Centrelink review and her application was turned down again.

"To be told you're not disabled enough when you can barely get out of bed some days, you can't understand how somebody can judge you that way," she said.

While applying for the DSP, Ms Hunwick received a Newstart allowance but a medical exemption meant she didn't have to search for a job.

Ms Hunwick has difficulty with her mobility. ( ABC News: Curtis Rodda )

Ms Hunwick is one of a record number of people with disabilities being put on Newstart payments, with Centrelink having denied their applications for the more generous disability support pension.

Ms Hunwick's application was overturned by the Administrative Appeals Tribunal in June this year, which effectively ordered Centrelink to approve her for the DSP.

"Why would you want to make it so hard for somebody who's already living such a hard life?" she said.

About 200,000 people with a disability on Newstart

Disability Advocacy Network Australia CEO Mary Mallett said the shift towards Newstart is a "huge concern" because there is a significant financial difference between the DSP and Newstart.

The basic rate for Newstart is $555 per fortnight, whereas the DSP is about $370 more, at $926 per fortnight including supplements.

"Many of [the recipients] have additional costs just because they have a disability," Ms Mallet said.

Rachel Park knows all about those additional costs, after being diagnosed with an aggressive form of MS in 2017.

Her symptoms include severe fatigue, muscle pain, blurry vision, memory loss and partial paralysis on the left side of her body.

Ms Hunwick has to take many medications for her conditions. ( ABC News: Curtis Rodda )

Like Ms Hunwick, the 24-year-old also thought it would be straightforward when she submitted her DSP application to Centrelink.

"I kind of assumed that they were going to be medical professionals. But they are not," she said.

Her application was rejected last spring and she was put on Newstart.

"I have to go see Disability Employment Services every fortnight and I have to do a job plan and apply for a certain amount of jobs per month," she said.

Rachel Park believes the 'invisible' nature of her MS contributed to Centrelink's rejection of her application for the DSP. ( ABC News: Mark O'Leary )

To meet her Newstart requirements, she sends online inquiries to employers and said she rarely gets a response.

Ms Park said her neurologist and doctor advised her not to work.

"When it comes to MS, you really just have to focus on your health... if I get too emotional one day, or I'm too stressed, my left side dies and I'll be limping around," she said.

For Ms Park, receiving Newstart instead of the DSP has had a big impact, and she's now moved back to Brisbane from Sydney to live with her parents.

Her additional expenses including medicine, specialist appointments and therapy to slow her muscle wastage, which can add up to $500 per month.

"[The DSP] would be a huge difference because I wouldn't have to rely so much on my parents," she said.

"Just getting the little money on Newstart, it just makes your life so much harder."

On good days, Rachel Park can still walk her dog. But within minutes, her MS can lead to partial paralysis and extreme pain. ( ABC News: Mark O'Leary )

How did we get here?

There wasn't always such a large gap between Newstart and the DSP.

In the late 1990s, the Government decided pensions such at the DSP should be benchmarked against a statistical measure called Male Total Average Weekly Earnings (MTAWE).

Newstart wasn't benchmarked, and was instead tied to increases in inflation, measured by the Consumer Price Index (CPI). As long as CPI increased, so would Newstart. But then, inflation stalled.

"The inflation rate has flatlined over the last 20 years. Therefore the Newstart rate has flatlined, whereas the DSP rate, the average male weekly earnings rate, has increased significantly," said John Berrill, a lawyer who advises DSP applicants.

In 2002, there was just $52 difference between the two payments. The DSP was $421 per fortnight and Newstart's basic rate was $369 per fortnight.

Today, the gap between Newstart and the DSP per fortnight has ballooned to more than $370 per fortnight.

Points system for measuring disability blamed

One of the biggest hurdles to accessing the DSP is satisfying 'impairment tables', which award points to applicants based on their disability.

"The vast majority of clients and doctors think that if you can't work long-term, you're eligible for DSP. That's the old world, that's not now," said Mr Berrill.

"You now need to have in addition to that, 20 points on these impairment tables. And that's the killer where people are missing out on these DSP applications."

Despite having MS and other auto-immune conditions, Ms Hunwick was forced onto Newstart. ( ABC News: Curtis Rodda )

The 15 impairment tables, covering disabilities from limb function, to vision, to intellectual cognition, were introduced in 2012.

Advocates believe many applications for DSP are rejected because Centrelink doesn't accept the evidence provided by applicants, and doctors are too overwhelmed to provide the information Centrelink requires.

"Most of the doctors they're dealing with are in the public system, they're very time-poor … they don't have the time to go to the website to look at what the requirements are for this points system," Mr Berrill said.

In 2011, before the impairment tables were introduced, nearly 60 per cent of DSP applications were successful. By 2018, that had dropped to less than 30 per cent.

Mr Berrill describes impairment tables as 'blunt instruments' to measure disabilities. ( ABC News: Patrick Stone )

That's not a coincidence, according to Mr Berrill.

"The DSP requirements are being used as a blunt instrument to deny people DSP and funnel them to Newstart, which is a much cheaper rate," Mr Berrill said.

The number of people receiving the DSP peaked at 830,000 in 2014. By late 2018 that number had shrunk to 750,000.

A spokesman for Social Services Minister Anne Ruston said in a statement the impairment tables are a big part of the reason for the reduction.

"The former Labor government amended the tables used to assess work-related impairment for DSP, which has significantly contributed to the decline in the number of Australians entering that payment."

The statement said the Government invests more than $800 million a year to help jobseekers with a disability, injury or health condition participate in meaningful work through Disability Employment Services.

But many people with a disability on Newstart such as Rachel Park would rather focus on their health, instead of having to search for a job.

She will have to meet the Disability Employment Services requirements for 18 months until she can get the DSP and the level of support her medical team said she needs.

"I just makes me feel so helpless. And I just feel so stuck," she said.

"I just feel like I can't get on with my life."