Deputy Prime Minister Plodprasop Suraswadi warned on Tuesday that more storms may follow Wutip, which weakened from a typhoon into a tropical depression when it hit Thailand, bringing heavy rain.
Wutip entered Nakhon Phanom on Monday night and moved inland, causing downpours in the province and in Nong Khai, Loei, Sakon Nakhon, Phetchabun and Uttaradit.
The chairman of the Water and Flood Management Commission declared that the tropical depression no longer poses any danger, but stressed that the country is still facing other possible storms after Wutip passes.
Floods have so far caused 23 deaths this year, and are still ravaging 25 provinces, mostly in the North and Northeast, the Disaster Prevention and Mitigation Department said.
Provinces experiencing the worst of floods include Ubon Ratchathani, Si Sa Ket, Prachin Buri and Ayutthaya.
The Disaster Prevention and Mitigation Offices in Ubon Ratchathani and Si Sa Ket predicted that flood levels will decrease over the next three days as officials drain water into the Moon River, a tributary of the Mekong.
Mr Plodprasop said the situation in Prachin Buri's flooded Kabin Buri and Si Maha Phot districts was improving because water is flowing down to Prachantakham and Muang districts, but said the situation in the provincial business town is still "serious".
He blamed a poor city planning in Kabin Buri for obstructing water flow, and said a plan to construct a new canal to guide water from the Prachin Buri River to Bang Pakong is under consideration.
The Disaster Prevention and Mitigation Office in Prachin Buri said the water level in Kabin Buri decreased by 12 centimetres on Tuesday, but was increasing in Muang district. Seven districts in the province have hit by floods.
In Ayutthaya, eight districts remained flooded including Phra Nakhon Si Ayutthaya.
Officials in Ayutthaya warned that water levels in the districts are continuing to rise, due to water being discharged from the Chao Phraya, Pasak Jolasid and Phra Rama VI dams.
Wutip left a trail of destruction in its wake with at least three people reported dead in Vietnam Tuesday, roofs ripped off thousands of homes and dozens of fishermen missing.
Roads were flooded, sea dykes damaged and power lines torn up along the central coastline, including in top tourist attractions such as the World Heritage Site of Hoi An and the ancient capital of Hue.
In Hoi An, an old trading port known for its traditional wooden architecture, streets around the river were under water although the main tourist districts were not affected, city officials said.
Flooding was also reported in Hue and authorities warned there could be more rain coming.
High winds ripped the roofs off around 95,000 houses and tens of thousands of hectares of crops were destroyed after Wutip - packing winds of up to 103 kilometres an hour - hit the country.
Vietnamese Prime Minister Nguyen Tan Dung put local authorities on high alert for flash floods and landslides in the aftermath of the typhoon as officials battled to clear up the worst of the damage.
China deployed navy warships and aircraft on Monday to search for survivors after three of its fishing boats sank in rough waters whipped up by Wutip, leaving more than 70 people missing.
Panorama by Sithikorn Wongwudthianun