Auckland rail workers are to strike over the introduction of driver-only trains.
The operator Transdev and the Rail and Maritime Union have been in collective bargaining since May.
Union organiser John Kerr said Transdev was refusing to back down on its proposal to reduce crews and run driver-only trains.
Mr Kerr said that would put passengers and drivers at risk by dividing drivers' attention and increasing the chances of an accident.
Transdev was reducing staff to cut costs and increase profit, he said.
The strike is scheduled to begin at 2am on Friday, concluding at 2am on Saturday.
Wellington rail workers went on strike in November over Transdev's attempts to remove longstanding conditions from staff collective agreements.