A girl in year 7 at Birrong Girls High School, in Sydney's west, reportedly told fellow students  she liked the terrorism organisation Islamic State and she was happy about recent attacks in Paris and Beirut.

On Wednesday, Mr Piccoli warned students they could face serious consequences for discussing the attacks in a favourable light.

"If you think this is a joke, you will find yourself in significant trouble," Mr Piccoli said.

"No right-minded person in Australia would do anything but condemn the atrocious attacks in Paris last week. We expect students to do the same thing."

He told the state's educators that any signs of pro-Islamic State sympathies among students should be reported immediately.

"We don't take any risks here. Anything that a teacher, or a principal or a student ... think is of concern, they should report.

"I would urge students not to muck around about this. You don't muck around when you go to airports. Students should know that you don't muck around on this, either."

A spokesman for the Department of Education said that comments supporting any terrorist activity were to be deplored and would not tolerated in public schools.

"The department is investigating comments allegedly made by a Birrong Girls High School student in support of the Paris attacks," he said.

"Strong disciplinary action will be taken against the student if it is shown such comments were made."

The investigation comes three weeks after the Baird government announced a $47 million package to help counter violent extremism in schools.

Teams of former principals, psychologists and student support workers, along with 200 extra counsellors, will identify vulnerable students and refer them to support programs.