A commuter train derailed in Wellington during morning rush hour on Monday, causing minor injuries to four people and disruption for hundreds of passengers.

The incident involved the 7.43 am service from Porirua to Wellington.

The last unit of the train came off the track near the Kaiwharawhara depot shortly after 8 am on Monday, Radio New Zealand reported.

KiwiRail general manager of passengers Deborah Hume said something punctured the floor of the unit, and engineers are working to establish what it was.

She said the derailment happened opposite the Interislander ferry terminal where many rail lines cross, so it caused a lot of disruption across the network.

Some 350 people were on board the train. KiwiRail said none of the four injured people was taken to hospital.

Nine other services were forced to stop near the Kaiwharawhara depot and hundreds of passengers had to walk from the halted trains to the nearest platform.

TranzMetro said all services on the Hutt Valley Line, Kapiti Line and the Wairarapa Line are suspended until further notice.

KiwiRail hoped to have train services operating by the afternoon peak time.