SINGAPORE - A localised power trip on Thursday morning (Aug 29) affected the immigration clearance system at Tuas Checkpoint, causing heavy traffic at the arrival and departure car zones for more than six hours.

The disruption to the system happened at 6.45am, said the Immigration and Checkpoints Authority (ICA), and it returned to normal at 1.30pm.

The ICA said the disruption resulted in “intermittent slowness”. The automatic clearance system and the clearance systems for motorcycles and bus zones were unaffected.

The ICA said the clearance system at the affected lanes progressively resumed from 8am. However, checks by The Straits Times of traffic webcams at around noon showed long lines of vehicles in both directions. The traffic appeared to have eased for departures at about 1pm, but there was still a backlog of vehicles waiting to enter Singapore.

The authority also said that at 11am, operations had to be temporarily suspended to secure a vehicle that evaded departure immigration clearance at the Malaysia checkpoint.

More resources were immediately deployed to manage the situation during the system disruption, with officers on night shift remaining behind to assist in the clearance of travellers, the ICA said. One of the departure car zones was also converted to clear arriving cars when the system progressively resumed.

The authority first warned about heavy traffic at Tuas Checkpoint at 7.24am, advising travellers to check the One Motoring website before embarking on their journey. In an update at 7.45am, it said the delays were due to an intermittently slow clearance system.

Traffic conditions worsened, as the timing of the power trip coincided with the morning peak period.

"ICA regrets the inconvenience caused to travellers who have taken a longer time to clear immigration," the statement said.

In a final update at 1.30pm, the ICA said the system had returned to normal at Tuas Checkpoint but the traffic remained heavy.

Frustrated motorists turned to social media platforms to post pictures of the jam at Tuas, with many saying they had been stuck in traffic for hours.

Some netizens complained that they needed a toilet break.

In another update at 10.45am, the ICA said Woodlands Checkpoint was experiencing heavy departure traffic as well. This was because of heavy backflow of vehicles from Malaysia. It is not known what caused the heavy backflow.