SINGAPORE - Motorists who were heading to the west on the Marina Coastal Expressway (MCE) on Tuesday (March 19) experienced a wet morning when tunnel fire sprinklers were accidentally activated.

A video posted on Facebook group Singapore Taxi Driver shows water raining down on vehicles in an MCE tunnel.

Motorcyclists are seen stopping at the side of the expressway to don their raincoats before carrying on with their journey.

The video prompted speculation among social media users that there was a burst pipe in the expressway tunnel.

In response to media queries, the Land Transport Authority (LTA) said on Tuesday that the water-based firefighting system in the westbound tunnel was triggered at 7.10am along a 25m stretch of the MCE, after the East Coast Parkway/Fort Road entrance.

An LTA spokesman said that the system had been accidentally triggered due to a technical fault, and was switched off at 7.26am.

LTA added that there was no fire or seawater seepage in the tunnel.

"There was some slow moving traffic near the affected areas of the tunnel during the incident, with no major impact to traffic," added the spokesman.

A reader who was on the way to work told Wanbao: "It was sunny outside, but 'raining' in the expressway. All the vehicles were drenched."

This is not the first time it has "rained" in the MCE. In January last year, a section of the eastbound MCE tunnel was closed for two hours due to a burst water pipe.

In May 2017, there was a similar incident when sprinklers were accidentally set off.

It happened near the exit to Fort Road. The expressway was not closed in that incident.