The Pan Borneo Highway authorities must learn from the highway collapse at the Tatau-Bintulu stretch in northern Sarawak and carry out immediate ground stability checks on other routes.

Social activist and lawyer Abun Sui said technical checks on other erosion-prone routes must be done now as there are signs the landas season would get worse.

"The collapse at the Tatau-Bintulu section (KM49) was severe (about 300m collapsed).

"The terrain that the Pan Borneo highway passes through is sometimes hilly and this increases the risk of erosion.

"Extensive checks on the soil stability are needed now before the landas (monsoon) gets worse," he said.

Motorists plying the Pan Borneo Highway must also be provided with the latest updates on major incidents that are disrupting traffic flow, said Bintulu DAP chairman Chiew Ching Sing.

The collapse of the Tatau-Bintulu stretch on Monday afternoon had caused a traffic diversion, he said.

Chiew, who is also Tanjung Batu assemblyman, said the highway builder was putting in round-the-clock effort to open two temporary lanes to divert traffic.

Chiew said the workers at the site and the traffic police were doing their best to alleviate the traffic congestion at the site.

However, until today traffic congestion persists as many motorists were still caught unaware.

"I was informed by many motorists that they end up being caught in the traffic confusion as the collapsed part is being repaired by the company in the Pan Borneo construction project and the Public Works Department.

"It will be good for the relevant authorities to keep motorists updated every hour on what is happening at the site," he added.

Chiew said the initial report was soil erosion caused by heavy rain brought cracks to that portion of the highway.

The cracks worsened and caused the eroded section to completely collapse.

Chiew said the route is the main link between Bintulu to Tatau and onwards to the rest of southern Sarawak.

There are many cargo trucks and containers as well as public buses and passenger vehicles using that route daily.

The traffic police at the site are diverting traffic to alternative village roads that connect Tatau to Selangau.