An historic cannonball found in Transmission Gully was "almost certainly" stolen by an on-site worker.
Three years ago, a 56kg cannonball was unearthed from a Porirua Stream by New Zealand Transport Agency contractors as they cleared a path for the new Transmission Gully highway.
Independent archaeologist Mary O’Keeffe examined the object over several months and said she believed it was a cannonball from a battle in 1846 between Māori leader Te Rangihaeata and Crown forces.
However, one day she came to work and the artefact was missing.
Now, Heritage New Zealand Pouhere Taonga is calling for its return.
“It would almost certainly have had to have been someone from the project because this is a secure office within the project boundaries so no one can just walk past,” Ms O'Keeffe said.
After allowing substantial time for the thief to return the cannonball with "no questions asked", a police report was filed last year, she said.
1 NEWS asked NZTA for comment, but a spokesperson said the responsibility for the cannonball sat with the contractors.
A spokesperson for the Transmission Gully project declined an interview but said in a statement "the cannonball was held in a secure on-site location".
"It was later discovered to have been removed from that location. After a range of efforts to encourage it’s return, it is now considered to have been stolen," the spokesperson said.
As for Ms O'Keeffe, she’s disappointed as there is further analysis of the ball that could’ve been done.
“I could've had a specialist look at the actual material it’s made of to try and see what the components were, see if we could work out an age, other aspects like that, so of course those lines of inquiry are no longer possible,” she said.
She said her findings indicate the artefact is linked to a battle nearly 200 years ago.
“There was a confrontation at Battle Hill in 1846 between the local Māoriand Government troops about land acquisition and land purchase."
Her theory is that the cannonball was fired from a ship’s gun.
“One of the ships may have sailed around the coast to just by Titahi Bay and done some blind firing over the ridge,” she said.
Ngāti Toa’s Te Waari Carkeek said the historical value was in the human story associated with the cannonball.
“The cannonball represents the colonial forces, that cannonball had the name of Rangihaeata and his people on it,” he said.
Ms O’Keeffe wants the cannonball to be returned so she can finish her research.
“Just bring it back, as an archaeologist that's all I want,” she said.