Dykes along the rain swollen Yom River in Sukhothai gave way on Monday, causing major flooding that inundated an estimated 500 households in the province's commercial area.
Prime Minister Srettha Thavisin told reporters the flood situation in Sukhothai was worrying because of the unrelenting rainfall over the province.
He did not say if he would visit flood-hit Sukhothai, but confirmed he would travel on Friday to Ubon Ratchathani province, where major flooding is expected soon.
Mr Srettha met the Royal Irrigation Department's deputy director-general on Monday to discuss flood impact prevention measures.
Local officials said on Monday that Sukhothai was hit by rising water levels. The Yom River was almost eight metres deep as it flowed through the province. The river walls reportedly could contain water levels below 8.15 metres.
The municipality is placing more sandbags at Phra Ruang Bridge above the Yom River to prevent higher water levels flooding local government buildings such as city hall, the provincial court as well as a police station, post office and residential areas.
Chamnan Chutiang, director of the Phitsanulok Provincial Irrigation Project, said that flooding had also affected 135,000 rai of land in the adjacent province of Phitsanulok.
He said storms in the northern region will increase the amount of rainfall, which will make the floods worse.
Phitsanulok governor Phusit Somjit said he had ordered government agencies in Phrom Phiram and Bang Rakam districts to prepare for major flooding as well as to plan drainage measures to prevent floods ravaging local rice fields.
Meanwhile, rising water in the Wang River has flooded Lampang, hitting 257 villages in eight districts, local officials said.
They said that the river water level has since subsided gradually in three districts. Locals said the flooding was the worst in 13 years.