The April Fools' joke about a school burning down in Sydney's northwest will now become a police matter.
Pranksters sent an SMS and email to parents of the Castle Hill High School in the early hours of Tuesday stating the school was closed and non-operational because of damage from a fire.
The Department of Education is not amused at the joke and has brought police in to investigate.
Many schools use an SMS and/or email system to contact parents and it was this database on the Castle Hill High School's IT system that was accessed illegally, according to Mark Davis from the Department of Education.
Some 1400 sets of parents received the text from the school's broadcast system at about 2.30am (AEDT).
Parent Suzy Tunks said she was woken at 2.30am by the text, and that the school's principal Vicki Brewer followed up with a corrective email, saying the report was wrong and the school remains open, as reported on News Ltd.
"It's not amusing to the department at all - it's very serious on a couple of levels," Mr Davis told AAP on Tuesday.
He said some parents had also called the police after receiving the false message.
Parents and students, especially those sitting exams on Tuesday, were made unnecessarily anxious, he said.
There was also the stress for parents who thought they had to make alternative arrangements for care.
Then there is the issue of data security, said Mr Davis.
The Department of Education will be investigating how the system was breached and make sure the system is tightened so it doesn't occur again.
The school is open as usual.
