Auckland Police are looking for three people after a Columbian man suffered a savage, unprovoked beating at Onehunga Train Station.

At around 1.40pm on Saturday, the 25 year old was sitting waiting for his train when a man came up and demanded his wallet.

When he refused, the vicrtim was kicked to the ground and continually attacked - suffering serious head injuries including a fractured eye socket and a deep gash to his head.

Detective Senior Sergeant Scott Armstrong says the extreme level of violence is very concerning.

Police are asking for the public's help to identify the attacker, and two other people who were at the station - a man wearing camouflage pants and a blue top, and a woman wearing a blue and black jacket.