Thailand fears floods once more as heavy rain in provinces could spread to Bangkok.

Fears have been raised after up to a quarter of Thailand's provinces, including the tourist resort of Ayutthaya, have been hit by floodwaters.

Thousands fled their homes in northern Thailand after heavy rain caused a major river to overflow at the start of the month, sending up to a metre of water into some towns. So far, four people have died.

The Bangkok Post today reported that the city's Metropolitan Administration has put all 50 districts on alert for 'possible flooding' as heavy rain is forecast between tomorrow and September 17 around many parts of the country.

Concern: A view of residential areas submerged by floodwaters in the Sukhothai province, northern Thailand

It said regions of the city had been told to install water pumps in areas prone to the floods and that thousands of people in vulnerable districts had been warned to be ready to move, should they need to.

Scenes of residents wading through waist-high water and stacking large sandbags around shops and homes in Sukhothai, around 430km north of Bangkok, are a stark reminder of last year's floods that killed more than 800 people.

The Foreign and Commonwealth Office - which then advised against all but essential travel to the capital, as well as central, north-eastern and eastern Thailand - has warned visitors about the current 'localised flooding' in Sukhothai.

Awash: Thai residents are evacuated with boats in a flooded street in Sukhothai

Today, website The Nation reported that the floodwaters in the region had 'begun to stabilise' although water levels were continuing to rise in Phitsanulok, also in the north.

Industrial estates have scrambled to build flood walls and dredge nearby canals in time for this year's rainy season - which runs from May to October, with September and October the height of the monsoon. But other parts of the country remain vulnerable to sudden inundation.

A landslide on September 8 meant the rail service between Lampang and Chiang Mai was suspended, with the FCO urging travellers to contact their booking agents.

In the dry: A family make their escape in a boat as water floods their town

The floods come amid concerns that the country's government failed to act fast enough to strengthen flood defences after last year's devastating floods which swept down into Bangkok.