Bus drivers in Wellington will begin an indefinite strike next Tuesday.

Photo: RNZ / Richard Tindiller

The strike will include drivers from two of four companies that run bus services in the region; Tranzurban, and Uzabus.

An agreement has been struck between the union and NZBus, and a vote to ratify it will be held at a stop work meeting tomorrow.

Mana Coach services already had a collective agreement.

Striking was the only option left to union members, Tramways spokesperson Kevin O'Sullivan said.

"We have exhausted every possible way of avoiding that, no one has really wanted to listen and so we'll just have to see how it pans out."

The union had offered an olive branch to the two companies, Mr O'Sullivan said. If Tranzurban and Uzabus had allowed their employees to go to a stop work meeting tomorrow, the strike action would have been suspended.

"They've told us today they're not going to do that, so industrial action will start at 2 o'clock on Tuesday morning."

Mr O'Sullivan said union members would continue to strike until their demands around a collective agreement were met.

About 145 drivers from the two companies, Tranzurban and Uzabus, were unionised.

Services on 11 routes would be cancelled between 9am and 3pm tomorrow due to the stop work meeting, and other services could also be affected, Metlink said.