KiwiRail has slashed its freight service on the Northland-Auckland line by half, but says the volume of freight transported will essentially be the same.
But the move has brought a stinging response from Northland MP and New Zealand First leader Winston Peters, who has called for "heads to roll" among the KiwiRail board.
KiwiRail has confirmed it has cut its weekly freight train on the Northland-Auckland line from 20 movements a week (10 each way) to 10 a week (five each way) from Monday this week.
The reduction comes after freight stopped going on the line between Otiria and Whangarei on August 31, meaning that cargo - logs - would now be transported by road.
A spokesman for the state-owned railway company said that like any freight business, KiwiRail looks for ways to move freight as cost efficiently as possible.
"KiwiRail has been working with its customers using the Northland line and consolidated their requirements to one daily train. The change frees up operational resources to be used elsewhere."
He said KiwiRail had worked with its customers to consolidate their freight needs to one daily train, but was unable to provide figures on how much tonnage would be on the trains.
"However, essentially the volume of freight carried will remain unchanged. If new commercial volumes are there we will reinstate trains.
"We are already in discussions over new opportunities," the spokesman said.
"The line remains open between Auckland and Otiria and should freight volumes at a commercially acceptable return be made available, KiwiRail is committed to providing services."
Mr Peters said the decision to slash the service was a disgrace, being done under subterfuge and heads should roll on the KiwiRail board over it.
"The result will be a significant drop in tonnage and it comes just weeks after KiwiRail shut down the Otiria-Kauri line - or movements on the line - whilst ministers in Parliament keep saying the line is still open," he said.
"If KiwiRail is doing the Government's bidding and shutting services as forecast, effectively they're shutting down critical rail services to regional New Zealand.
"Meanwhile, multiple unit leviathans are heading down our highways causing enormous damage to roads and creating major safety issues.
"This is one further disgraceful KiwiRail decision and death by a thousand cuts for the provinces."