Army experts were called to an Auckland landfill after a training bomb was found dumped at the gates.
The bomb was discovered near the Constellation Drive Refuse Transfer Station in Albany on Sunday.
Inspector Les Paterson said it was unclear who dumped the bomb, but it was assumed they had intended disposing of it at the landfill. However when they found the site closed, they left it nearby.
"The area was closed off for about an hour. The NZ Defence Force bomb disposal staff arrived and inspected it, announcing it was inert," he said.
Businesses in the vicinity were evacuated while the inspection was carried out.