The Defence Force carried out a controlled explosion on the shell. Photo: NZ Police
The shell was discovered a few days ago by a worker connected to the dredging of the shipping canal, police said.
The person contacted police, who called in the New Zealand Defence Force to assess the bomb.
A controlled explosion was carried out by the Defence Force today, police said.
"The head of the shell is thought to be more than 100 years old, and may have been used in coastal defences," police said.
