Auckland police are hunting a man who allegedly punched an elderly train manager while he was working and knocked him unconscious.

The incident happened about 4.30pm on March 28 on the Western Line between New Lynn and Fruitvale stations.

Detective Senior Sergeant Megan Goldie said the train manager had sat down to do some work. Next to him, a man and woman were having a verbal altercation, Goldie said.

“The woman has then gotten up and moved to sit across from the victim.

“Seconds later, completely unprovoked, the man has come over and punched the victim a number of times, rendering him unconscious.”

The pair then got off at Fruitvale Station.

Goldie said it was lucky the elderly victim did not have more serious injuries.

The victim was doing okay, but was shaken, she said.

Auckland police are looking for this man - pictured at New Lynn train station - after an elderly train manager was knocked out on March 28. Photo / New Zealand Police

This man and another woman got off at Fruitvale Station after a train manager was knocked out. Photo / New Zealand Police

“The violence shown by this [offender] is extremely concerning and police are very keen to find out who he is so we can hold him accountable,” Goldie said.

“The victim was simply doing his job when he was violently assaulted. We cannot accept this type of behaviour in our community.”

Goldie said police hoped someone might recognise the man.

Goldie said anyone who knew this man should phone police on 105 and quote file number 2400330/3374. People could also offer information anonymously via Crime Stoppers on 0800 555 111. Photo / New Zealand Police

Police also hoped they could identify the woman he was with and ensure she had support available should she need it.

Goldie said anyone who knew this man should phone police on 105 and quote file number 2400330/3374. People could also offer information anonymously via Crime Stoppers on 0800 555 111.