The Transport Workers Union has called off a planned strike by bus drivers tomorrow that threatened to throw the travel plans of tens of thousands of passengers in Melbourne, Geelong and Ballarat into chaos.

Drivers employed by Transdev and CDC had announced plans to stop work for 24 hours over stalled negotiations regarding pay and conditions.

Between them the two companies are responsible for running roughly half of Melbourne's bus network.

The breakthrough came after Treasurer Tim Pallas and Transport Minister Jacinta Allan met with TWU representatives late yesterday, urging the union to call off the planned action.

The government also met with bus operators, who returned to the table today with a revised offer.

TWU Secretary John Berger said the proposed deal would be put to members for a vote.

9NEWS understands both unions have agreed to call of the strike. (Nine)

"As a show of good faith in the bargaining process we have called off tomorrow’s action involving members until that vote takes place," he said.

But he warned drivers could take further protected action, should the new offer fail to win approval.

The deal means all Transdev and CDC services will operate tomorrow as scheduled.

Meanwhile, Premier Daniel Andrews has made it clear transport will form a key part of his election platform, promising the "biggest transport building program in Australian history".