UPDATED 5:14pm: Police are promising to change the way they deal with drunk and mentally unwell people.

Four police officers that dealt with a heavily intoxicated Sentry Taitoko the night he died in a police cell are the subject of an employment review.

An Independent Police Conduct Authority report into the death of a 20-year-old Manurewa man has been released today.

Taitoko died in custody last year. He was heavily intoxicated, had taken drugs and posed a risk to himself when he was arrested last March.

Chair Judge Sir David Carruthers said he hit his head 114 times, until there was blood smeared on the wall of his cell.

"Formal monitoring requires checks by visitors to the cell at least five times per hour. He was not checked at all for about 50 minutes after 4:26am except by way of CCTV observation."

Acting Assistant Commissioner Barry Taylor says he accepts the report in full.

"Our aim would be to work with other agencies and other organisations to prevent these people being placed in police custody."

Counties Manukau District Commander John Tims says one of the officers has since resigned, and another has moved to a new role.

He says the other two are being looked at currently.

"There have been some breaches of policy and this will be dealt with through the perfomance framework."

Tims says he accepts the report, and is apologising to the Taitoko family.

The police complaints body has painted a picture of a force overwhelmed by the job of holding drunk or vulnerable people in custody.

Sir David said police sometimes fail their legal obligation to care for people, "simply because they do not have the necessary expertise and training to deal with some of the challenges presented by people being held in police cells."

The report has made a generic assessment of the way police deal with prisoners, following 31 complaints and incidents in the past three years.

Sir David says as a result, there are too many instances of attempted suicide and self-harm.

"It is unacceptable that, in many police districts, the standard response to deal with a person who's experiencing a mental health crisis or is heavily intoxicated is to detain them in a police cell."

Advocate Nigel Hampton QC says a similar report in 2011 showed 27 people died in police custody in the decade prior.

"I suspect not a lot of progress has been made, particularly in terms of the provision of proper facilities for intoxicated and/or mentally disabled people."

Hampton says recommendations from a similar report in 2011 still haven't been implemented.

"Sensible as they almost inevitably are, they fall on deaf ears. They're seen as toothless recommendations, there's no bite to them."

Sir David says aspects of that report are still being put in place.

"A number of those have been implemented, others are work in progress and have required a long term solution."

The family of Taitoko hopes police get a real wake-up call from the report into his death.

Lawyer for the family of Sentry Taitoko, Barry Wilson, says it shows just how ill-prepared they are.

"It's a landmark case and a major rocket for people who are in charge of police custodial management."

Wilson, says people have a strong expectation for improvements to be made. 

"Now that it's been highlighted in the public mind people will be alerted to the dangers and they'll be watching the police closely."

Labour's spokesperson for police and corrections Kelvin Davis says the report needs to front-up to lots of questions.

"His treatment when he was arrested and in the subsequent four or five hours until he died - (we want to know) why wasn't he examined medically. We understand his behaviour was extreme in the cells so how do police get around that."