The governor checked out Mah Boonkrong, Siam Paragon, Siam Discovery and Siam Centre shopping centres in the afternoon.

Apirak learned that additional security measures had been taken, including removing refuse containers except at security posts, using bomb-detection dogs and installing closed-circuit-camera surveillance inside and out.

Security guards patrol round the clock.

The operators of the centres in the busy part of town are meeting monthly to evaluate security threats and ensure precautions are up to scratch.

Siam Paragon has installed bomb-detectors for bags.

Meanwhile, city police remain on high alert after Australia, Canada, Britain and Japan warned of possible terror attacks in Bangkok and urged their citizens to stay away from crowded places such as shopping malls and transport centres.

"The Metropolitan Police is on full alert. We've maintained our security measures at maximum levels since the bombs on December 31," its deputy chief Maj-General Kamol Kaewsuwan said.

Since the New Year's Eve bombs killed three and injured dozens, including foreign tourists, police have beefed up security at department stores, train stations and Bangkok's new international airport.