The Amalgamated Transit Union's president said people should be prepared for a messy commute in Halifax Monday morning. (CBC)

Striking Metro Transit workers in Halifax said Sunday they are preparing for a long contract dispute. Talks between the Amalgamated Transit Union and the city remained at a standstill over the weekend.

Sunday marked the fourth day of the strike that has been affecting more than 90,000 daily users.

Picket lines remained up across the city Sunday afternoon, and union president Ken Wilson said people should be prepared for a messy commute Monday morning.

"I think the longer this goes, the appetite from the public is going to get vicious — very angry and aggressive. I don't know if it's going to be [directed] at the union or the employer," he said.

Liberal Party Leader Stephen McNeil called on Premier Darrell Dexter to help resolve the strike, saying the walkout is having a significant impact on the half of the province's population that lives in the capital region.

McNeil said he wondered why the premier hadn't offered the services of the Nova Scotia Department of Labour and Advanced Education to try to resolve the dispute, or made a telephone call to urge the two sides back to the bargaining table.

On Thursday, Dexter said he wasn't getting involved in the dispute.

More than 700 workers walked off the job just after 1:30 a.m. on Thursday after union representatives rejected Metro Transit's latest proposal.