About 1000 bus drivers in Auckland will go on strike on Friday, their union has confirmed.
The First Union and Tramways Union are in a dispute with NZ Bus over pay and conditions.
A First Union organiser Rudd Hughes said the strike would have a big impact on traffic and they did not take the action lightly.
Mr Hughes said to avert the strike the company would have to arrange an early bargaining date and come to the table for meaningful talks.
Auckland Transport is looking at what contingencies it can put in place during the strike, but cannot yet say what these could be, nor whether it is looking at putting on extra train services.
The agency said it would be using the next 24 hours to see what it can do, but its main priority would be maintaining school bus services.
The industrial action involves drivers from the Metrolink, Go West, North Star and Waka Pacific lines.
Drivers from the Howick and Eastern bus services will be striking at the same time, the union says, but as part of a separate dispute.