Rescue teams in helicopters or on foot on Wednesday tried to reach thousands of people stranded in their houses, on trains and in open terrain devastated by floods triggered by days of heavy rain across several northern provinces.
The official toll stood at 26 people dead and 92 missing, but Suksan Wanaputi, governor of northern Uttaradit province, told Thai television: "We are worried that 100 people may have died."
Flash floods and mudslides triggered by torrential rains hit five mountainous northern Thai provinces - Uttaradit, Nan, Phrae, Lampang and Sukhothai - since early on Tuesday.
About 1,200 people have been evacuated so far, while more than 75,000 have suffered damage either to their homes or their farms, the Thai interior ministry said.
An aerial view shows the flooding
in Uttaradit province
Boonriang Chuchai-saengrat, chief health officer of Uttaradit province, appealed to government authorities to set up a disaster identification centre like one established after the Asian tsunami to record unclaimed bodies and temporarily bury corpses for later identification.
Saman Pangwatcharakorn, chief of the regional Disaster Prevention and Rescue Centre, said early on Wednesday that the search and rescue operation was suspended on Tuesday night due to darkness and would resume at dawn on Wednesday.
Thaksin Shinawatra, the prime minister who resumed his official duties on Tuesday after a seven-week leave of absence, was scheduled to inspect the disaster scene on Wednesday.