The Bjelke-Petersen Government decided to demolish Brisbane's Bellevue Hotel after a secret report warned the historic building would cost $2 million to restore.

The controversial decision to knock down the iconic building in 1979 remains shrouded in mystery, despite today's release of confidential cabinet documents from 30 years ago.

Demolished ... Brisbane's Bellevue Hotel. Credit:State Library of Queensland

The National Trust had been campaigning to preserve the three-storey Bellevue Hotel, which stood on the corner of George and Alice streets and was built in the 1880s.

Cabinet documents show that the then-premier, Joh Bjelke-Petersen, took a submission to his frontbench colleagues arguing it would be costly to fix major faults in the building's structure.