The Armed Offenders Squad is to use a girls' school in Dunedin for a training exercise on Monday.
Police say they will hold a simulated emergency event at Otago Girls' High in Tennyson Street between 3pm and 5pm.
Other emergency services and general police staff will also be involved.
Police say residents and businesses around Otago Girls' High should not be alarmed if they hear loud bangs and gunshot sounds.
They will not reveal details of the simulation, but say a small number of teachers and students will be involved, and parents have been fully informed.