Malaysian authorities believed the poisoning was caused by toxic waste dumped into a river near the schools in Johor.
"Unfortunately, I was told today that the situation is getting more critical," Minister of Education Maszlee Malik said in a statement on his official Facebook page.
The number of people treated climbed to 207 compared to 35 reported last week. By March 11, 44 were in hospital, 33 of them are pupils.
The minister ordered all schools within a three-kilometre radius to be shut immediately.
According to rescuers and firefighters, most of the victims are students and kitcheners, aged between 7-40, of the two affected schools.
Earlier, local authorities were forced to evacuate over 1,000 people, mostly school students, after chemicals were illegally dumped in a river near two schools in Pasir Gudang.
