Key talks between First Aberdeen and Unite have broken down.
First Bus and Unite the union have been in discussions today regarding new terms and conditions for drivers.
A turnout of 74.9% of Unite members who work for First Bus saw 98.4% opt to turn down the proposed conditions.
With 260 votes, only four union members voted in favour of accepting the offer.
First Aberdeen managing director Andrew Jarvis said: “Discussions continued today with the employee representatives following the recent workplace ballot.
“Regrettably, despite agreeing that the economic changes in the area over the last few years have significantly changed the level of demand for some of the services First Aberdeen operates, we have not been able to reach agreement on a way forward on changes to the terms and conditions for drivers.
“Individual consultations with employees will therefore commence and we will remain in close communication with the trade union over the coming weeks.”
Mike Flinn from Unite said: “We put forward a fair proposal with savings that we thought might lead to a compromise.
“However, First came back and said it wasn’t enough savings and they wanted to push ahead with the new terms and conditions.
“There has been a total failure to agree with each other and at the moment it means will push ahead with a postal ballot of our members for industrial action.
“It could be anywhere from between five to six weeks for us to come to a result for the postal ballot and then we give the company two-weeks’ notice of any industrial action.
“Drivers will have their chance to vote and they will still be angry that a solution hasn’t been reached.”