Dunedin's Bayfield High School will open as normal today, after its second online threat in a year

The Andersons Bay school was sent into lockdown around 8.30 yesterday morning.

Around 550 students and staff were then evacuated from the school - which closed for the day.

Police have arrested a 16-year-old in relation to the incident, after searching a property yesterday afternoon.

Investigations are continuing and Police are providing support to the school.