A second landslip in eight days has occurred near the Tampines Expressway (TPE) slip road towards Loyang Avenue.

The Land Transport Authority (LTA) announced on Sunday that continuous rain caused the slope erosion.

The landslip was detected by LTA engineers and contractors who had been monitoring the slope, after seven drain railings along a monsoon drain gave way in a similar incident on Jan 2.

"Preliminary investigations indicate that the stability of the slope is not affected," LTA said in a Facebook post.

On Sunday night, the slip road was closed for repair works.

In an update yesterday morning, LTA said that one lane of the slip road has been reopened.

The other lane remains closed while slope repair works continue. "Besides this slip road, motorists may continue to use alternative routes to get to destinations around the area too," it added.

Responding to queries from The Straits Times, an LTA spokesman said that the authority will continue to monitor road conditions closely and take any necessary precautionary measures to ensure public safety.

The latest landslip on the same slope was expected and more could follow.

"Repairing one spot where the slope fails does not ensure that another spot on the slope will not fail," said Associate Professor Leong Eng Choon from the Nanyang Technological University's School of Civil and Environmental Engineering.

The possibility of more landslips on the same slope increases when one spot of the slope has previously failed, he added.

According to Prof Leong, the best possible precautions to ensure the safety of the slope have been taken in the light of the wet weather.

"Due to current weather conditions, it is difficult to carry out effective slope remediation work. The next best solution is to cover the entire slope with canvas sheets - as has been done beside the repaired spot, but not for the entire slope - to prevent further rainwater infiltration from weakening the slope," he added.

Intermittent rain over a long period of time may also increase the possibility of landslips as more rainwater enters the slope.

On Sunday, the National Environment Agency said this was the wettest January of the past 30 years, with recorded rainfall of 623.8mm.

This exceeds the 600.9mm recorded in January 2004.