Police are seeking witnesses to an indecent assault involving a boy who was travelling on a Wairarapa train service on Monday.
The incident happened at about 4.45pm when the train was somewhere between Lower Hutt and Woodside.
Police said an unknown male assaulted a boy, who was not injured but understandably shaken by the incident.
Police would like to speak with concerned members of the public who intervened and assisted the boy.