Police investigating a serious assault in Māhia on New Year’s morning are asking any witnesses to come forward.

A 34-year-old man was knocked unconscious, suffering a concussion and facial injuries, after he tried to break up an altercation between an unknown group of people about 12.40am.

The victim was hospitalised but has since been discharged.

"This should have been a night of celebration and sadly hasn’t turned out that way," says Detective Sergeant Stephen Smith.

'We know the fight involved between 20 to 30 people in a carpark of a Newcastle Street hotel, and it was likely witnessed by a number of people."

Detectives from Wairoa and Gisborne are investigating and need to hear from anyone with information or footage. 

This can be provided by calling 105, or by making a report online at 105.police.govt.nz, using Update Report. 

Please quote the file number 240101/2665.

Information can also be provided anonymously via Crime Stoppers on 0800 555 111.