Thailand's university drop-out rate is likely to shoot up after devastating floods kept schools closed for weeks and affected hundreds of thousands of students, officials said Wednesday.

Thailand's worst floods in decades, which have killed more than 600 people, have also caused an estimated seven billion baht ($224 million) in damage to educational facilities, Education Minister Worawat Ua-apinyakul told AFP.

"Some 2,600 educational institutes -- both public and private -- and around 700,000 people (involved in education) have been affected," he said.

The floods have damaged millions of Thai homes and livelihoods and as a result are hampering students' ability to pay their fees, said Sukhum Chaleysub, who runs opinion polls at Bangkok's Suan Dusit Rajabhat university.

"Because of the floods, they have told us they can't afford to pay their tuition and said they may have to drop out to help their families," he said.

Sukhum said the number of students who have said they cannot afford to pay their tuition bills has shot up to between 10 and 15 percent -- more than double the usual rate of around 5 percent.

The Bangkok Metropolitan Administration (BMA) said late Tuesday that hundreds of schools across the capital will be closed for another week, with many in flood-hit outer suburbs likely to stay shut until mid-December.

Around 15,000 flood evacuees are sheltering in the empty school buildings, which did not re-open after a month-long holiday ended early November, and these people will have to be moved before classes can resume, according to the BMA statement.

Arunee Ninkaew, who cares for her 10-year-old grandson Pornpiphat Jaadbanterng in the Don Mueang district of Bangkok, said she was worried he would fall behind with his school still shuttered by the flooding.

"But the school said it will open on December 6. They will finish classes at 4:00 pm instead of 3:00 pm and students will have to go to classes on Saturdays," Arunee told AFP.