A steel plate covering a hole near Soi Sukhumvit 64/1 collapsed on Wednesday under the weight of a heavy truck that ended up taking six hours to remove.

The road surface collapsed as the 10-wheel truck passed over it about 11.45am, beneath the skywalk of the Punnawithi BTS station where the Bangkok Metropolitan Administration is putting electrical wiring and cabling underground.

Two people were injured and were taken to a nearby hospital, police said.

Traffic on the three inbound lanes of Sukhumvit Road was brought to a halt, causing a traffic jam that extended back to the Bang Na intersection and beyond.

A backhoe was brought to the scene to remove the dirt out of the truck, and two more trucks arrived to carry the dirt away. Two cranes then were brought in to lift the truck out of the hole, with the task completed around 6.30pm.

It was still not known when repairs to the site could be made in order for traffic to resume.

Thai Rath newspaper pointed out that there are about 700 locations on Bangkok roads where steel plates cover entrances to tunnels for electrical cables.

Bangkok governor Chadchart Sittipunt, who visited the scene in the afternoon, told reporters that no workers were in the hole when the accident occurred. The cabling work normally takes place from 10pm to 5am, he said.

He said it was not known yet if the truck exceeded the weight limit or whether the construction of the covering was substandard.

Numerous netizens noted a suspicious sticker on the truck's front windshield. It was the same as those shown earlier this year that were used in a long-running corruption racket that allowed overloaded trucks to avoid police checks.