About 600 Rail and Maritime Transport Union (RMTU) members employed by Ontrack gave the company notice of planned industrial action two weeks ago to begin tonight at 4pm.

RMTU advocate Scott Wilson said both parties were meeting in Wellington today and it was a final opportunity for Ontrack to up a standing pay offer and avoid a total ban on overtime and callouts by union staff.

Mr Wilson said Ontrack had refused to make a pay offer amounting to any more than the rate of inflation.

Ontrack said the company was not in a position to be able to do so and was disappointed at the union's approach.

It said it hoped negotiations today would lead to the industrial action being averted.

The action would involve staff from Invercargill to Northland.