Australia's only dedicated support service for people with eating disorders is set to be axed next year, under a shake-up of online mental health services.

Key points: The only dedicated eating disorders support line set to be axed

The only dedicated eating disorders support line set to be axed More than 1 million Australians suffer from eating disorders

More than 1 million Australians suffer from eating disorders Anorexia has the highest death rate of any mental illness

Mental health experts are devastated, saying the phone and web support run by the Butterfly Foundation has saved countless patients' lives.

Christine Morgan, the Butterfly Foundation's chief executive, said the helpline assisted more than 1,000 people each month, with patients receiving up to an hour of phone and web counselling.

"We've been told we only have another 12 months of certain funding for it," she said.

"To be honest, it fills me with horror because at the moment, this is the only national dedicated service for people with eating disorders."

The Butterfly Foundation is the country's peak support organisation for people with conditions such as anorexia and bulimia.

The Federal Government is developing a new centralised online "gateway" as part of its shake-up of mental health services.

A letter from the Federal Department of Health, obtained by the ABC, says: "It will bring together and streamline access to existing evidence-based information, advice and digital mental health treatment and connect people to services through a centralised telephone and web portal."

Experts say, while streamlining services may be worthwhile, it is crucial that specialised services are still available.

Ms Morgan said patients needed very specific services for eating disorders.

"Somebody suffering an eating disorder does not get the appropriate care and counselling if they ring in a general mental health line," she said.

St Vincent's Hospital psychiatrist Liz Scott said many of her patients regularly used the Butterfly Foundation's support service.

"If this was something like cancer affecting young people, we wouldn't be saying, 'well let's take away the phone support line' or 'let's withdraw services'. There would be a major community outcry," Dr Scott said.

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She said eating disorders carried very high rates of mortality.

"One in 10 people who suffer from an eating disorder are dead within 10 years, and if you think about these disorders affecting young people, that's a horrifying statistic of something that is potentially preventable," she said.

The Federal Government said people seeking help would go to the new digital gateway and be prioritised to specialist services, like that provided by the Butterfly Foundation.

People ringing in or using web chat would be asked a list of questions which would determine what kind of help they needed.

The Government's expert reference group identified that some of the helpline services were doubling up on what they were offering patients.

But the ABC understands that the Butterfly Foundation's unique services, that no-one else offers, would be safe.

A further 20 mental health groups are also facing an uncertain future, when it comes to their online services, including Lifeline and SANE Australia.

Phone line 'a safe place to turn to'

Kath Courts hopes the support line can be saved. ( ABC News: Sophie Scott )

Kath Courts, 26, who is being treated for an eating disorder, said she had used Butterfly Foundation's phone and web support to get through tough times.

"Calling the phone line was just so important to have that safe space to turn to, to tell someone how I was thinking and feeling and be believed and validated for that," she said.

Ms Courts said friends with eating disorders had contacted other mental health lines and were told to "go for a walk" or "have an ice cream".

"To be told to eat something pleasant, it's like you have absolutely no idea what I'm going through, I really need help and I'm not getting it," she said.

Ms Courts is hoping the Federal Government will give assurances the support line will be saved.