Flood levels were subsiding in five lower southern provinces, with nearly 70,000 households affected from the disaster, the Department of Disaster Prevention and Mitigation (DDPM) reported on Wednesday.
The five provinces were Narathiwat, Pattani, Satun, Songkhla and Yala, while 68,941 families were affected, said DDPM director-general Chaiwat Junthirapong.
In Narathiwat, 13 districts, namely Bacho, Chanae, Cho Airong, Muang, Rangae, Rueso, Sri Sakhon, Sukhirin, Sungai Kolok, Sungai Padi, Takbai, Waeng and Yi-ngo, still experienced flooding, affecting 39,604 families.
Preecha Nualnoi, deputy governor of Narathiwat, said on Wednesday that floods had killed six people, including an 89-year-old woman and a toddler, in the province.
Another person was still missing following days of intense rain, which sparked floodwaters that reached around three metres in height in some places, Mr Preecha said.
Some rail services in Narathiwat, which borders Malaysia, had resumed following days of closure due to track subsidence, he said.
Pattani reported flooding in eight districts of Kapho, Khok Pho, Mai Kaen, Muang, Nong Chik, Sai Buri, Thung Yang Daeng and Yarang, and 8,360 families were affected.
In Satun, many areas of Khuan Don district were inundated, affecting 1,801 families.
In Songkhla, flooding was reported in Khlong Hoi Khong, Rattaphum and Sabai Yoi districts, and 836 families were victims.
In Yala, six districts were flooded, namely Bannang Sata, Kabang, Muang, Raman, Than To and Yaha. There were 18,340 flood-hit families.
On Tuesday, Prime Minister and Finance Minister Srettha Thavisin travelled to Narathiwat to get a first-hand look at the flood situation in the southern region.
Thailand's rainy season typically brings months of daily deluges, but scientists say man-made climate change can make rainfall more intense.