EMERGENCY services are investigating the circumstances surrounding pupils falling ill at Saint Francis Xavier Primary School in Ballarat.
Police, paramedics and the CFA hazardous material unit are currently on the scene to establish the reason for the pupils falling ill.
Principal Paul Bissinella said 10 children in Year 4 were sent home after they began coughing, complained of stomach cramps and some started vomiting.
Pupils from all other classes will remain at the school as normal.
He said emergency services were called, but were still unsure of what had caused the symptoms. He said no one had reported the smell of gas.
"At this stage our primary concern is the safety and well being of all our kids," he said.
Mr Bissinella said no pupil had been transported to hospital at this stage.
"We've relocated other classes away from the area ensure their well being," he said.