Emergency services were called to the scene near Elizabeth St, in Waikanae, shortly after 6.15am.
Police said no one was injured, but roads near Waikanae Station were closed and services on the Kāpiti line suspended.
The train appeared to have been a freight service with no passengers, a police spokesperson said.
Commuters rushed to help the truck driver after the vehicle was hit by the train, Waikanae commuter Monika Baker told RNZ.
"It was one of those huge flat bed trucks that had a huge digger truck on the back... as I was going on up onto the train station, I saw that very same truck was trying to turn left crossing the tracks, and for some reason it had stopped with the driver's cabin just on the track.
"I thought, 'Well I hope it's going to move - because there's a train coming in soon'."
She said she heard the bells and knew the freight train was arriving.
"There were quite a few concerned people already looking towards that truck and we thought surely it's going to move or the train is going to stop.
"And it didn't - and the train just went right into that truck cabin."
Baker said the engine and lights of the truck were damaged in what she described as a "huge crash".
"People started running towards the truck and wanted to make sure the driver got out safely."
Emergency services arrived shortly after, she said.
