Artillery shell detonated in Wellington park

File photo / NZ Herald

An artillery shell from the 1860s was detonated in a Wellington park this afternoon after it was discovered buried beneath a suburban home two days ago.

Wellington police acting tactical response manager Senior Sergeant Hamish Milne said the shell was found by builders who were strengthening the foundations of a house in Berhampore.

The Defence Force bomb disposal unit was then called in to take care of it.

"They identified it as six-pound artillery shrapnel shell which was commonly in use around 1860...and they made the decision that the best course of action was to move it to a nearby safe location and destroy it there,'' Mr Milne said.

As a precaution, the police specialist search group would search under the house where the shell was found to check if there are any others.

Wellington police communications manager Nick Bohm said the shell, which was about the size of a two-litre milk bottle, was probably a relic from a barracks that was on the property in the 1900s.

"They come up every now and again as people do earthworks. I wouldn't say that they're common but they do crop up every now and again.''

Fifty homes and part of a retirement home close to a Newtown park were evacuated as a precaution before the shell was destroyed this afternoon.

Student Aidan Milner, 19, who had to leave his home, heard the explosion from beyond the cordon.

"We didn't see it but we definitely heard it. It was louder than I expected,'' he said.