DUE to a glitch in the Woodlands Checkpoint's computer system, travellers trying to get into and out of Singapore were caught in a massive jam on Sunday night.

At 10.48pm, the Land Transport Authority's traffic cameras (at www.onemotoring.com.sg) showed a line of traffic backed up in both directions at the Causeway. At the Tuas checkpoint, however, traffic was sparse.

An Immigration and Checkpoints Authority (ICA) spokesman said the system had been "experiencing slowness" since before 10pm, but is back online.

It is investigating the cause, and that passengers were still being cleared through the checkpoint when the system was down.

Mr H.C. Seah, 59, a semi-retired Singaporean living in Johor Bahru, said he had moved only 20m in half an hour.

He described the situation as "chaotic", with frustrated motorists sounding their horns. When he called ICA, he was told its computer system was down.

"Why do they rely only on computers? They should have a Plan B," he said.