A police operation which took place at a number of schools across Sydney after numerous threats is now over.

Officers were called to nine schools, with at least two of those evacuated while police searched the grounds.

Students were temporarily moved out of Sydney Girls High School and Randwick Girls High School in Sydney's east.

A number of parents at both schools chose to take their daughters home early.

Police said the operation was "a precaution".

Pauline Kandidakis was among a number of parents who chose to pull their children out of Randwick Girls High School early.

"My daughters told me that it was a real evacuation, they were told it was a real evacuation and it was not a hoax, it was a bomb threat, so that is not kosher in my books," she said.

In a statement, police said they were liaising with the Department of Education.

The department confirmed police attended each school as a precaution.

"Each school is taking precautionary measures to ensure the safety of its students and no students are in danger," it said in a statement.

"Concerned parents can contact their child's school."

The operation follows the evacuation of six schools in Sydney and the Illawarra region on Friday after threats were received.

Police said they would investigate the threats.