Northbound train services between Marina Bay and Braddell stations are delayed due to a "rail crack", said SMRT on Saturday afternoon.

At about 3.40pm, SMRT posted on its Facebook page: "Trains will be travelling at a slower speed - in compliance to safety and recovery procedures."

"SMRT engineers have been deployed on site to carry out investigations and have installed G-clamps to secure the rail joint."

Passenger safety is a priority and trains will not run if safety is found to be compromised, SMRT added.