A man was left with a gash on his head after an attack at Waikanae Train Station, on the Kapiti Coast.
The 31-year-old man was waiting on the south bound platform at nine-thirty yesterday morning.
Detective Senior Sergeant Grant Ferguson of the Kapi Mana police said some sort of weapon was involved.
Mr Ferguson said it appeared the victim did not know his attacker.
Mr Ferguson said the man ran off across State Highway One after the attack and it was possible he got on a southbound train sometime later.
Police wanted to hear from anyone who witnessed the attack or who knows the identity of the offender.