SINGAPORE - Commuters were left frustrated after a signal fault caused significant delays on the Circle Line (CCL) on Wednesday (Nov 2) morning.

The fault, described by operator SMRT as an "intermittent" one, culminated in the disruption of train service between Botanic Gardens and Marymount MRT stations in both directions at around 9.10am. The disruption later extended beyond Marymount to Serangoon station.

Free regular bus services were also made available at all stations along the line.

Normal train service only resumed at around 10.27am, about three hours after SMRT alerted commuters to the fault.

In response to media queries, SMRT said in a statement the CCL had encountered intermittent signal interference which caused a number of delays along the network.

"This resulted in one train that stalled between Marymount and Botanic Gardens stations in the direction of Dhoby Ghaut," the statement added.

"We are sorry for the inconvenience caused this morning. Our engineering staff are investigating the matter."

SMRT first tweeted about the fault at 7.37am, informing commuters of an additional 10 minutes travel time between Pasir Panjang and one-north stations.

While it initially said the fault had been cleared, it warned that trains and stations were crowded due to congestion.

At 8.04am, SMRT said the signal fault was causing trains to move slower in the direction of Harbour Front station. It added that it was investigating the fault.

SMRT later revised the additional travel time to 30 minutes.

On social media, commuters complained of long queues, crowded stations and waits for trains that extended up to 30 minutes.