Wellingtonians who usually catch the train are being told to consider staying at home ahead of a major strike.

Rail and Maritime Transport Union members will walk off the job for 24 hours tomorrow.

That means there'll be no trains running in the capital from 2am Thursday until 2am Friday.

Metlink has posted a message on its website, telling people to make alternative transport arrangements, or consider not travelling at all.

It says on a regular weekday in Wellington, more than 30,000 passenger journeys are by train.

Metlink said with such short notice it can't source enough buses to transport that many people.

Union spokesman Wayne Butson told the NZ Herald, it was the first industrial action since 1994 to affect Wellington's rail system for longer than two hours.

He said the union didn't make the decision lightly.

"We've been trying to negotiate with Transdev and Hyundai since May this year, and they've stalled every single step of the way.

"We all regret the disruption this will cause for Wellington commuters, and we encourage them to ask the regional council, and their mayors, some hard questions about why big international companies are being allowed to run down good Wellington jobs."