Tongan authorities are expected to charge a local man with murder over the death of an Auckland policeman but are reluctant to elevate the assault charges faced by two of their own officers.

Otahuhu constable Kali Fungavaka, in Tonga to act as a pallbearer at his grandfather's funeral, was arrested for drunkenness on August 27 and taken to the police cells in Nuku'alofa.

In circumstances yet to be fully explained, he was allegedly assaulted by at least three men and knocked unconscious.

He was taken to Vaiola Hospital and placed on life-support, which was switched off on Thursday.

His wife Audra and four children were present when he died soon after.

Yesterday, two policemen and a civilian, Kalisitiane Manu, appeared before a magistrate and were remanded in custody to another hearing on Monday.

"The matter is before the court now, it is still a grievous bodily harm, but we are looking to elevate the charges now that the man has died," Tonga's assistant police commissioner Viliami 'Unga Fa'aoa told Fairfax Media.

He said he expected that Manu would be charged with murder, but not the policemen.

It was likely the body would arrive back in Auckland today (Saturday).

He would not discuss the investigation but state run Tonga Broadcasting reported yesterday that Fungavaka hit one of the policemen while he was being arrested. The police did not do anything at the time but Fungavaka was taken to the police station.

Tonga Broadcasting says the two arresting police officers then assaulted him and he was then thrown injured into a cell with five men. One of the men is alleged to have given what police believe was the fatal blow.

His family could not be contacted for comment, but one relative on social media strongly denied the dead man had thrown the first punch.

Watts described the day her husband died as "a date I will never forget, but will never want to remember....Kali fought long enough for the children to see him, hug him and tell him how much they love him."

Underscoring the seriousness of the death, Tonga's Prime Minister Lord Tu'ivakano yesterday visited Watts and the family.

Tonga's King Tupou VI is currently in New Zealand and will be entertained at an Auckland City lunch on Monday.

Tonga, which has long had a reputation for police brutality, is sensitive about laying full murder charges because the penalty is a mandatory death sentence.

- © Fairfax NZ News