Jane* has lived with severe depression and anxiety for the last 15 years outside a small town in rural Victoria.

Key points: Advocates fear as many as 200,000 Australians might lose support in transition to NDIS

Advocates fear as many as 200,000 Australians might lose support in transition to NDIS People say support like home visits and therapy has been life saving

People say support like home visits and therapy has been life saving Commonwealth-state funding divide creates confusion over how support will be provided

For much of that time, she's felt isolated and alone in her struggle with her mental illness.

"I've had several attempted suicides," she said.

Jane has no doubt where she'd be if she wasn't getting help through home visits and therapy.

"I wouldn't be here. I'd be dead. I would be dead," she said. "Having those social supports, as well as the professional support, is the reason why I'm here. I wouldn't be here otherwise."

She's currently supported with an Individual Client Support Package paid for by the Victorian Government.

But that could all be about to change. As states transition to the National Disability Insurance Scheme (NDIS), support programs which have helped people like Jane will no longer be funded.

And adding to her anxiety, Jane now has to wait to find out if she'll be admitted to the NDIS. Even if she is, she's not sure she'll get the same level of care that she receives now.

Jane is not alone. An estimated 230,000 Australians receive support for a number of psychosocial illnesses, including bi-polar disorder, depression, anxiety, and schizophrenia.

It's estimated about one quarter of them will eventually be admitted to the NDIS.

Thousands might miss out on support: advocates

Today mental health advocates are meeting MPs and key ministers during a parliamentary advocacy day in Canberra.

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Their fears over a looming service gap in the transition to the National Disability Insurance Scheme will be front and centre.

"We're concerned that in the order of 200,000 Australians might miss out on support that they would otherwise be entitled to," said Frank Quinlan, chief executive of Mental Health Australia.

There's no clear picture of just how many people will miss out because psychosocial support is delivered by federal, state and territorial governments. There's currently no national database keeping overall track of who's being helped.

"We think a very large number of people will be affected by these changes, but frankly we don't know exactly how many," said Mr Quinlan.

"We know that there are people in state government programs. We know that there are people in Commonwealth Government programs. And that many of these programs are being wound up."

Two of the big Commonwealth programs providing psychosocial support that will be rolled into the NDIS are Personal Helpers and Mentors (PHAMs), and Partners in Recovery.

They currently assist nearly 33,000 people living with psychosocial illness.

"Without the PHAMs people, I wouldn't be here," said Deborah*.

"I'm 53, and my anxiety got so bad that I ended up in hospital. Because I actually thought I was going to die."

Deborah lives in Canberra, where the NDIS is already rolled out. When she applied with the help of the Woden Community Service, she was rejected.

She's worried about how she'll cope when the PHAMs program is phased out next year.

"I was having, you know, really bad suicidal thoughts," she said.

What happens to people who miss out under the NDIS?

The Department of Human Services says about 80 per cent of participants with a psychosocial disability who submitted access requests were eligible for the scheme.

A department spokesperson said in a statement, "Community mental health services remain primarily a state and territory government responsibility".

The Commonwealth-state divide in providing support for those with psychosocial illness only adds to the confusion over the NDIS transition.

The administrators running programs that offer psychosocial support say the biggest issue now is confusion — especially about what happens to those who miss out on the NDIS.

"You've immediately got a gap. Even if you took in the 64,000 (to the NDIS), what happens to the rest of the community?", said Elizabeth Crowther, chief executive of Wellways, a leading not-for-profit mental health and disability support organisation.

The Department of Human Services said in a statement: "Each government has pledged to provide continuity of support for existing clients so that current clients not eligible for the NDIS continue to receive support."

But with state and Commonwealth programs due to be phased out in the NDIS transition, right now no one knows how governments will make good on those pledges.

"I believe the government are trying like crazy to work out what the strategy is," said Elizabeth Crowther of Wellways. "We're really, really worried about it."

*Names have been changed