The investigation into the stabbing of a Waihi holiday-maker was upgraded to a homicide inquiry after the victim died in hospital on Thursday.
New Zealander Robert Wilkinson - who was 64 and visiting from Australia - died from injuries to his face and neck after he was attacked outside his caravan in the early hours of New Year's Day.
A post-mortem will begin in Auckland on Friday.
Detective Inspector Chris Page says the tragedy of Mr Wilkinson's death will be felt by the wider Waihi community.
He's urging anyone with any knowledge of the attack, or the offender, to come forward.
More than 30 police staff are now involved in the homicide investigation.
The weapon used to kill Mr Wilkinson has not yet been found.
The 20 police personnel initially working on the investigation has been boosted, with more expected to arrive in Waihi Beach from across Waikato and Auckland over the coming days.
Investigators are hoping photographs taken by revellers in the area at the time of the attack will give clues, and have asked for people to email their pictures to police in Thames.