A mid-morning bomb scare in Tauranga has been defused, with nothing more than a replica German stick grenade to blame.

Police and firefighters rushed to the Port of Tauranga's customs building on Mirrieless Road at about 10.35am this morning after reports of a grenade-like object being uncovered in a routine container x-ray.

Sergeant Tristan Murray discusses the find with customs officials this monring. Photo: Luke Balvert.

Tauranga Police Sergeant Tristan Murray says a NZ Defence Force bomb disposal unit, who travelled down from Auckland, inspected the item and at 1pm confirmed that they are satisfied it is a replica.

'It's an inert but realistic German stick grenade replica,” says Tristan.

'The container came in from the UK and was obviously being processed by customs as they normally are. And that particular object wasn't listed in the consignment.”

This particular type of grenade was the standard hand grenade of the German Army from World War 1 until the end of World War 2.

Its distinctive appearance led to it being labelled a 'stick grenade”, or a 'potato masher” in British Army slang, and is today one of the most easily recognised infantry weapons of the 20th century.

Tristan cannot comment on what else was listed in the container, referring further details including whether charges will be laid to New Zealand Customs Service officials.

But he is happy with the precautionary steps taken by staff to evacuate the surrounding area upon discovery.

At the time people had been evacuated from the customs and neighbouring Sandfords buildings, with a number of workers seen congregated on the road nearby as police treated the item as a possible live grenade.

'They did the right thing,” adds Tristan, 'which is to not touch it or go anywhere near it and evacuate the area.”

Customs NZ external relations manager Helen Keyes says the documentation stated that the container contained antique firearms, which was why it was being examined.

"No decision has been made as to whether the replica will be seized and/or the importer fined or prosecuted for not declaring it.

"Our investigations continue and we will talk to the importer before making a decision.

"If we decide not to seize the grenade we will give it back to the importer."