A childcare centre and a building on a marae have been evacuated following the discovery of explosive material in a Nelson park.
Members of the public are urged to avoid Founders Heritage Park in Atawhai Drive while the Defence Force's explosive ordnance disposal unit assesses the material.
The park's carpark has also been closed as a safety precaution.
Police said there would be a visible police presence in the area for the next couple of hours while the unit disposed of the material safely.
"Police want to acknowledge the public for their patience and co-operation while the assessment is carried out."
It is unknown what type of explosive material is involved.
Police said staff were working closely with the explosive ordnance disposal unit to ensure the incident was managed safely.