This is the amusing moment a clinic sign floated away as floods turned streets into raging rivers in Thailand.

Footage shows a health centre marker being swept away by the strong current, drifting down the inundated roadway in Pattaya, Chonburi province, on July 1.

One passerby jokingly said: 'So this is what a mobile clinic looks like.'

Roads were left swamped in up to 28 inches of floodwater following two hours of relentless rains that overwhelmed the city's drainage systems.

The Meteorological Department warned that more thunderstorms were expected in 60 to 70 per cent of the area. Southwesterly winds were predicted to churn up waves up to 7ft (2 metres) high off the coast.

Thailand and neighbouring countries in Southeast Asia are in their annual monsoon rainy season which sees soaring temperatures followed by powerful rain storms in the afternoon leading to widespread flash floods.