A hole was found in the middle of Rama IV Road in Klong Toey on Monday and workers are trying to repair it before motorists and commuters hit the road after work.
Sansern Ruengrit, an official of the Drainage and Sewerage Department, said the one-metre-deep hole appeared on the busy road in front of the Metropolitan Electricity Administration head office in Klong Toey district. Underneath was a cavity of around 3m long.
The cause remained unknown as of 4pm.
City Hall workers are repairing the road surface before the rush hours, expected to begin at 3-4pm.
Traffic Police Radio said the repair could take about two hours.