A KiwiRail proposal to move its health and safety team from Wellington to Auckland is being slammed as "nonsensical" by the Rail and Maritime Transport Union.
The proposal applies to Zero Harm personnel, tasked with driving KiwiRail performance in health and safety.
The union said the plan could affect 40 staff at minimum but a KiwiRail spokesperson said there were only 33 Zero Harm personnel, and just five in Wellington.
Union general secretary Wayne Butson said it was only informed about the plan by its members, and many Zero Harm staff would not want to move.
They saw the proposal as "code" for getting rid of railway staff and replacing them with staff who have no experience running a rail network.
"If that was to occur and we end up with a whole lot of people who don't know anything about running a rail service then we're actually setting ourselves up to be anything but zero harm."
The plan could make railways less safe because experienced staff would be replaced with outsiders, Mr Butson said.
But KiwiRail spokeswoman Jenni Austin said they need to move personnel to the most risky regions, rather than being centralised in Wellington.
"It should also be noted that our biggest activity is rail freight, and the busiest parts of the rail network are in the upper North Island," she said.
She said there had not yet been a significant number of staff moved from Wellington.