Chilling 16-word handwritten note man left before his body was found in the shallows of one of Australia's most popular beaches

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A man whose body was found in the shallows of a popular Sydney beach wrote a chilling note on his hospital discharge papers moments before he died.

Jason Murphy's body was found by surfers at Cronulla Beach, in the city's south, at about 6.30am on March 23.

Police said the 39-year-old's death was not being treated as suspicious. 

Days later, his sister Lydia Murphy revealed her brother spent his final hours in the mental health unit at St George Hospital.

He suffered from severe insomnia and voluntarily admitted himself because he was battling with thoughts about self-harm.

Ms Murphy said he was discharged from hospital alone, 'in a state of delusion and extreme confusion', and was found dead hours later.

His final words were scrawled on his discharge papers: 'If you find this well I done it and took my life, please call the authorities'.

Jason Murphy (pictured) admitted himself to hospital, before his body washed up on a Sydney beach

His sister Lydia Murphy (pictured) launched a petition to change policies surrounding mental health patients

Ms Murphy was his next of kin, but says the hospital did not call her to say her brother had been released from the mental health unit or that he had been considering self-harm.

She launched a Change.org petition last week to try and change healthcare policies and make it mandatory for health facilities to notify a friend or family member when a mental health patient is discharged.

'I strongly believe if a call was made to me, being Jason's next of kin, then I would have been aware of his need for support that day,' she said.

'The system is flawed and there is to many lives being lost to deaf ears and to an overrun system.'

A spokesperson for NSW Health told Daily Mail Australia there is an investigation into the way Mr Murphy's case was handled.

'The care provided to Mr Murphy following his voluntary admission to St George Hospital, including the circumstances surrounding his discharge from care, are being investigated by NSW Health,' the spokesperson said.

'South East Sydney Local Health District met with Ms Murphy last week to listen to her concerns about her brother’s care, answer her questions.'

Surfers found Jason Murphy's body int he shallows at Cronulla Beach on March 23

The spokesperson said the department expressed its sincere condolences, and that it would keep Ms Murphy informed about the progress of the investigation.

A close friend, Johana Wallace, set up a GoFundMe page on Saturday to raise money for Mr Murphy's funeral.

The siblings have no other family to help cover the costs, and Ms Murphy had spinal surgery in December and has not been able to work.

'Lydia is the kindest person and will always be there for others but finds it very hard to ask for help as she has always only had herself and her brother to rely on,' Ms Wallace said.

'With the passing of her brother and not having any family or parents to help her with funeral arrangements and expenses, she has been left alone to navigate and work it all out.'

Mr Murphy's funeral will be held in Sydney's western suburbs on April 12. 

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