Unionized container truck drivers at Canada’s largest port will vote on Saturday on whether to join their non-unionized colleagues in a job action, after hundreds of truckers walked off the job over services and pay.

The non-unionized drivers said they will not return to work at Port Metro Vancouver until their concerns are resolved.

Unifor, which represents about 400 unionized drivers at the port, said its members are also frustrated over issues like long line-ups for loading and unloading, and a lack of standardized pay rates.

“This morning’s protest is just the beginning,” said Unifor local president Paul Johal in statement. “Truckers are prepared to escalate job action if the port and both levels of government don’t take our concerns seriously.”

After the vote, the unionized workers are required to give 72-hour notice before walking off the job.

The United Truckers Association of British Columbia (UTA), a non-profit group representing union and non-union drivers, and Unifor have both been in talks with the port authority for months over concerns that long wait times at the facilities were costing drivers money. Truckers are paid by the load and do not make money while sitting in line.

They are demanding that the port streamline operations to improve wait times or pay drivers a fair hourly wage while waiting. They are also asking for a standardized pay rate for all container truck drivers working at the city’s port.

A spokesman for Port Metro Vancouver confirmed that the action Wednesday had had an impact on business at the port, which handled a record 135 million tonnes of cargo in 2013.

“The port is still open for business, but we are seeing delays due to the protest today,” spokesman John Parker-Jervis said.

Port Metro Vancouver has said it is working on new infrastructure and practices to improve wait times at its facilities, and blamed some of the backlog on extreme weather. (Reuters)