Police have lifted a cordon around a Christchurch school put in place after shots were reported this morning.

Armed police cordoned off Hills Rd and Innes Rd near Mairehau High School after reports of gunshots just before 11.30am today.

Inspector Alan Weston said the shots from a property in the area were reported by a neighbour.

Almost 500 students were placed in lockdown while police investigated.

Police said two people were helping them with their inquiries.

Mairehau head girl Devon Smith was outside the school when the alarm sounded and she was not allowed back in. She said her friends inside kept away from windows and hid under desks.

Principal Harry Romana said he was proud of how his students and staff reacted.