South Australia's peak doctors' union says it has taken its most "drastic action" ever by referring the state's health department to the Australian Human Rights Commission over "cruel" treatment of mental health patients.

Key points: Treatment of mental health patients in SA is "discriminatory, cruel and unacceptable", doctors say

Treatment of mental health patients in SA is "discriminatory, cruel and unacceptable", doctors say The doctors' union has written to the Australian Human Rights Commission asking for an investigation

The doctors' union has written to the Australian Human Rights Commission asking for an investigation The health department has defended its record, saying it is working to reduce waiting times

Mental health patients can often wait up to five days to be seen in the state's emergency departments (EDs), according to the South Australian Salaried Medical Officers Association.

Senior industrial officer Bernadette Mulholland said mental health patients were treated as inferior to patients with physical conditions and the department had "failed" to eliminate that discrimination.

"It certainly is drastic action but drastic situations require drastic actions and we're left with no alternative," she told ABC News.

"We've never been required to take action like this but the situation has become quite dire … and [doctors] felt so cruel, that they asked us to escalate that action.

Ms Mulholland said the union had never been required to take action like this before. ( ABC Radio Adelaide: Malcolm Sutton )

"We see no choice but to be the voice for mental health patients, given that they're some of the most vulnerable patients in our community."

She said the union had been raising the issue of long wait times for mental health patients with the South Australian health department and local health networks for more than four years, but said the situation had only worsened.

According to the Australian Institute of Health and Welfare (AIHW), South Australia has the highest mental health-related ED presentations in the nation.

It also found South Australian hospitals had some of the longest wait times in Australia for mental health patients in emergency departments.

Ms Mulholland called on the Australian Human Rights Commission to investigate the concerns and discrimination in South Australia but has also called for it to undertake a national review, citing similar issues in New South Wales and Victoria.

'Discriminatory, unacceptable and cruel'

In a complaint sent to the Australian Human Rights Commission, the union described the treatment of mental health patients as "discriminatory, unacceptable and cruel".

It said the constant noise, lighting and disruption in hospital emergency departments had only exacerbated the patients' mental health conditions which had led to an increase in physical and chemical restraint and increased usage of security guards.

"These vulnerable patients are unable to advocate for themselves and are treated as an inferior class of patient in terms of resourcing and response from the administration, the Department of Health and Wellbeing and the hospitals," the complaint said.

"The appalling lengths of stay in the emergency departments had, and still have, a significant impact" on the condition of mental health patients.

"There is an inequality of care given to patients with mental health issues compared to patients with a physical condition."

The letter said conditions created what was "clearly not an appropriate therapeutic environment".

Ms Mulholland said mental health patients and their families would be "well within their rights" to sue the Department of Health and Wellbeing over the treatment and conditions they had experienced.

'They didn't know what to do with me'

Jacki Brune speaking about suicide prevention. ( ABC News: Carl Saville )

Earlier this year, South Australia's Jacki Brune shared her experience of being in and out of hospital for the past 23 years just to stay alive.

With no intensive community-based mental health programs in her hometown of Port Pirie in South Australia, she had no choice but to go to hospital when she was at risk of suicide.

"I was having really bad panic attacks, really bad panic attacks all day, everyday for six months and it just got to the point where I [tried to take my life] because no-one was helping me," Ms Brune said.

"I'd go to the doctor, I'd go to the emergency, I'd lost so much weight and I was a mess.

"I suppose they didn't know what to do with me until I broke, and I broke in a big way."

Advocates said Ms Brune's experience was not unique, with mental health patients increasingly forced to present to South Australian emergency departments because of a lack of community-based support programs.

They have said beds for mental health patients in the state's hospitals are often in short supply with patients forced to spend hours, sometimes days, waiting in emergency departments.

A forensic mental health patient also spent four days restrained in the Royal Adelaide Hospital's (RAH) emergency department because there were no secure beds available in any Adelaide hospital, it was revealed earlier this year.

In a statement, SA Health said it shared concerns with current waiting times in emergency departments and it was working to resolve the issues.

"We are concerned about ED wait times for mental health consumers," the department said.

"We are working to reduce this through initiatives such as opening 10 additional forensic beds, establishing a purpose-built short-stay unit at the Lyell McEwin Hospital, a future Urgent Mental Health Centre and a range of strategies in the Mental Health Services Plan, which will be released soon."