VANCOUVER -- There's still time for the two sides in the SkyTrain workers' contract dispute to reach a deal and avoid a strike, but TransLink is warning commuters to plan for the worst.

On Monday, TransLink CEO Kevin Desmond told riders to expect an "extremely disruptive" commute if the latest round of bargaining talks fail and the Expo and Millennium lines are shut down Tuesday.

"To be very clear, there is no way to replace a system that reliably moves 150,000 people per day," Desmond told reporters.

"Many people will be left with no other options to get around the region."

But TransLink noted most of its services will be up and running, including the regular bus system, SeaBuses, Canada Line, West Coast Express and HandyDART.

However, there will not be any additional buses or West Coast Express trains operating to help with what's expected to be a huge influx of passengers who would normally be on the SkyTrain.

TransLink said it was told additional bus service was not possible "given operational constraints and labour considerations."

CUPE 7000 and the B.C. Rapid Transit Company agreed to a media blackout amid ongoing negotiations, and Desmond declined to comment on the state of bargaining Monday afternoon.

"I don't want to characterize where they're at right now. They're bargaining and they're going to stay at the table as long as they can to reach an agreement," he said.

During the bus workers' contract dispute, which was resolved with a new three-year collective agreement last Thursday, the B.C. government said it had no desire to intervene in the bargaining process. On Monday, Premier John Horgan indicated the same was true for the ongoing talks.

"Any agreement is best found at the bargaining table. An imposed agreement – a settlement that's forced – does not resolve the issues that led to the impasse," Horgan said.

Unlike the bus workers' union, CUPE 7000 has not set a midnight deadline for an agreement.

Sunday's bargaining continued in the early morning hours of Monday, so commuters might not learn what their options will be until they wake up on Tuesday.

With files from CTV News Vancouver's Allison Hurst