Bangkok's Chao Phraya river is expected to rise up to 2.6 metres above sea level during high tide on Saturday.
The centre of the Thai capital is bracing itself.
The combination of record high tides and flood waters running down from the north have combined to bring the river close to its brink.
Flood warnings have been stepped up and residents still in the city are being urged to head to higher ground.
Thousands have already fled Bangkok - others are still reluctant to go.
SOUNDBITE: Jakarin Kajornburi, Bangkok resident, saying (Thai):
"I've tried to live like this but the water keeps rising. If the water level gets higher than this we might have to evacuate."
Thailand's prime minister is appealing to the people and the world to have faith in the nation's ability to handle the crisis.
Yingluck Shinawatra says the country's worst floods in half a century could start to recede next week.
SOUNDBITE: Thai Prime Minister Yingluck Shinawatra saying (English):
"Bangkok is the last destination to the ocean. That's why now is the peak and the worst in Thailand. So hopefully next week will start to settle and back to normal soon."
The floods have submerged 1.6 million hectares.
That's an area the size of Kuwait or Swaziland.
The disaster, caused partly by unusually heavy monsoon rains, has also claimed at least 377 lives.
Paul Chapman, Reuters
Comments