The Australian Defence Force's largest operational air base experienced a security breach last month after a man was able to get inside the base, before later being arrested by police.

An "unauthorised man" was found at the Royal Australian Air Force base at Amberley, 40 kilometres south-west of Brisbane, around 3am on September 17, Queensland Police said in a statement.

The 46-year-old North Ipswich man was arrested by police without any further incident, a police spokesperson said.

Police are also investigating allegations the man was able to drive a forklift while at the base.

The police spokesperson said the man has been released and no charges have been laid, but the investigation is continuing.

"Police investigations into the matter remain ongoing with the assistance of Defence,

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