Drivers who rely on a major Metro Vancouver bridge will have to slow down while crossing the Fraser River.

The speed limit has been lowered by 20 km/h on the Alex Fraser Bridge, the province said in a statement Tuesday.

Decreasing the limit from 90 km/h down to 70 km/h is a change made at the same time as construction was announced, but it will be permanent.

The province also warned that two lanes would be closed on the bridge as of Tuesday, as crews remove painted lines and install temporary markets for the northbound lanes.

The work is expected to take three nights to complete, but it's weather dependent and the plan could change.

When the current phase wraps up, there will be a short break, then crews will return after the August long weekend to transition the southbound lanes and paint permanent lanes on the bridge's surface.

The changes are being made to accommodate an additional lane of traffic, bringing the bridge to seven lanes with a counter-flow system.