Christchurch Girls High had to be evacuated for an hour on Wednesday after receiving a number of bomb threats.
Principal Christine O'Neill said the school was evacuated at about 11.10am after it received three threatening emails from different email addresses.
"The police came on site along with some bomb experts and they thoroughly searched the school."
Nothing of suspicion was found and the school reopened at about 12.30pm.
A police spokeswoman said there is currently still a police presence at the school.
