Monsoon floods in Thailand now affect three quarters of the country.
The government said on Tuesday that 58 of Thailand's 77 provinces are inundated, 25 severely. Some 224 people are dead.
Wat Chaiwatthanaram, one of the best known temples in the ancient city of Ayutthaya, north of Bangkok, is closed to visitors.
The water level inside the temple grounds is reported to be now 1.5 metres.
The northern city of Chiang Mai is also badly hit.
Last week the government announced the deployment of about 10,000 soldiers and more than 100 boats, to help affected people.