A mystery object that closed a busy Queensland beach after being found washed up on Thursday morning has been identified as a practice torpedo.

Police were on the scene at The Spit on the busy Main Beach on the Gold Coast after the “suspicious device” was spotted by a dog walker and surf lifesavers about 5.45am.

A 100-metre exclusion zone was established while police and the Australian Defence Force examined the object.

Police later confirmed the device was an inert practice torpedo that had been used in a recent military drill off the Queensland coast.

It was not related to the recent activities of the Chinese military in the Tasman Sea.

The mystery object has since been confirmed as a practice torpedo. Photo: AAP

Acting Inspector Leon Wort said the ADF had boxed up the device and returned it to its depot.

“It’s been recovered and we’ve got no further concerns for public safety,” he said.

“The ADF will … work out what went wrong and why they couldn’t recover it.”

Wort thanked the passersby who alerted police and urged people not to handle suspect devices on the beach.

The Gold Coast beach has since reopened.

-with AAP