The Bangkok Metropolitan Administration (BMA) has asked people to work from home to avoid traffic congestion as heavy rain is forecast across the capital from Wednesday until Friday.

Motorists already experienced long tailbacks on Monday when afternoon downpours caused floods that lasted through the rush hour and on into the evening.

"So, the BMA has asked private company employees to work from home until Friday due to the forecast for heavy rain," said deputy Bangkok governor Tavida Kamolvej.

For those who have to work on-site, employers are requested to let them finish work early so they can avoid the worst of the jams caused by heavy traffic during storms, said Ms Tavida.

Ms Tavida acknowledged that drainage of floodwater has been slow, though most of the flooded areas in the city had been cleared by the end of Tuesday.

The BMA is piling up sandbags and building levees in flood-prone areas such as Laksi, Don Muang and Bang Khen districts.