Key Points:

Wanganui police have launched a homicide investigation after a 28-year-old man died following an apparently unprovoked attack in Wanganui.

The slain man has been named as Paul Shane Kumeroa who was the father of an 18-month-old son.

Detective Inspector Sue Schwalger said Mr Kumeroa was walking along Cross Street in the suburb of Castlecliff about 9.45pm on Tuesday when a vehicle pulled up and the occupants assaulted him in a vicious and what appeared to be an unprovoked attack.

He sustained head injuries and died this morning.

Mr Kumeroa's death had been reported to the coroner and a post mortem examination would be conducted later today.

Ms Schwalger said police completed their scene examination in Cross Street yesterday and were still speaking with family members and other people who had come forward with information.

Police would like to hear from anyone who had information about how Mr Kumeroa came by his injuries and also sightings of any vehicles in or around the area, she said.