An early-morning text message sent to hundreds of parents saying Castle Hill High School had burnt down has been exposed as an April Fools' Day prank.
The NSW Department of Education and Communities said it was reporting the incident to police after discovering that an unknown person had "inappropriately accessed" the school's IT system and sent hundreds of inaccurate text messages to students' parents early on Tuesday morning.
The text message incorrectly claimed that the school had been severely damaged by fire and that it was unsafe for students to attend that day.
Some parents reported being woken at 3am by the text message, which was also emailed to some parents.
"Feeling so SAD. received a message last night that Castle Hill High had been severely damaged (burnt) and that it was unfit for children to attend school. It just makes me so angry only the hall was spared," wrote one parent on social media, before the prank was exposed.
A NSW Department of Education and Communities spokesman said the message was sent to hundreds of parents who had provided their mobile phone number or email address to the school so they could receive important information.
"The information [in the text and email] was completely incorrect," the spokesman said.
"As soon as we became aware, the correct information that the school was open was sent to those who had received the initial SMS or email, and the school's website has been changed to reflect the information, as has the school's notice board out on the street.
"The school, along with the department, will be investigating how this occurred. It will be reported to the police because there is a question of data security there.
"It may have only been an April Fools' Day prank, but we want to make sure that data is secure, that no other data has been accessed and obviously work to strengthen the system so it doesn't occur again."
The spokesman said the message would have caused distress to some students who were due to sit exams at the school on Tuesday, while some parents would have scrambled to try to organise last-minute supervision for their children.
"Disadvantaging and distressing parents and students is something we obviously don't want," the spokesman said.
"We will be working with the police on this and obviously if we find out who is responsible and it is a member of the school community, we will be taking disciplinary action against them. Obviously if the police find criminal activity involved, they will take the action that is appropriate.