A patient who died following an incident at Christchurch's Hillmorton Hospital was left unresponsive for twelve hours before medical attention was sought, his family say.

Alain Closel was rushed to Christchurch Hospital in 2013, the same day he was found cold and pale by a nurse at the mental health facility.

Police investigating the incident have so-far been unable to pin blame.

However, Mr Closel’s grieving family say his death could have been prevented.

The 67-year-old’s son, Mark Closel, says he didn’t know his father was being cared for by staff at Hillmorton Hospital “until it was too late.”

A CDHB serious incident review report, obtained by NZME, shows staff failed to take the appropriate steps to care for the patient, who was known to fall over frequently.

“He was left on the ground and then put in a chair over a twelve-hour period and wasn't given medical attention...he was just sort of left,” says Mark Closel.

“The problem with that is [finding] who’s culpable. Who didn’t do what they should have done over that period of time...when you’ve got different staff on different shifts?”

Alain Closel’s life support was switched off on May 5 2013, as he lay surrounded by his family, his favourite song playing in the background.

Mark Closel says he’s angry at the standard of care provided by Hillmorton staff and the CDHB’s handling of the incident.

He’s pushing for changes so that no other family in a similar situation has to suffer.

““The system has gaps, it’s a systemic issue and a culture issue... if you’re going to change a culture you have to raise awareness."

Alain Closel, a volunteer patient at the facility, repeatedly told staff he wanted to leave in the days leading up to his death.

He was given medication on four separate occasions to relieve anxiety, a response the review team suggested may have been inappropriate.

"It would be appropriate to give [the medication] for agitation, but not in a response to leave hospital per se."

The investigation was unable to determine why nurses administered the drug, but found his family should've been told of Mr Closel's request to leave.

"This was a serious omission given that he was voluntary patient who was wanting to leave hospital."

"Concerns were identified regarding the potential infringement of Mr Closel's legal rights."

The report found that on a separate occasion, Alain Closel should have had a “thorough” neurological assessment done, along with a CT scan of his brain.

Both were never completed.

“Although this was not consistent with the expectations of senior medical staff, it seems that this was common practice at Hillmorton Hospital at the time,” the report says.

NZME understands a total of three unexpected deaths occurred at Hillmorton Hospital over the course of 2013.

Alain Closel was born in Mauritius before moving to New Zealand in his 20’s.

Music was a keen interest for him and he played in a band.

His family were of utmost importance to him, Mark Closel said.

“He stuck to who he is, and he’s quite authentic in that regard,” he said.

“It’s sad that we couldn’t be with him when he was getting unwell...we weren’t given the opportunity, and we weren’t given the opportunity to say goodbye.”