The buildings, which account for about 7 per cent of all office space in Brisbane’s CBD, include the David Longland Building at 63 George Street, Education House at  54 Mary Street, the Primary Industries Building at 62-80 Ann Street and Mineral House at 41 George Street.

The $561.9 million deal also includes towers at 61 Mary Street, 111 George Street and 33 Charlotte Street.

The buildings will be sold to fund controlled by the state-owned Queensland Investment Corporation to pay down close to half a billion dollars in government debt.

“The Government will lease back the buildings for periods of between four and 15 years,” Treasurer Tim Nicholls said in a statement on Friday.

‘‘We’ve negotiated set lease costs with fixed rent increases built in so we’re getting certainty around the costs of our office accommodation into the future.’’

Mr Nicholls said the proceeds would be used to write down the massive debt Labor bequeathed Queensland taxpayers.

“We estimate that by using these funds to pay down that debt we’ll save Queenslanders around $130 million in interest payments,’’ he said.

Mr Nicholls said the government had sought advice from two major real estate brokers, ‘‘who concluded the deal represented value for money’’.

The opposition has criticised the move, saying Premier Campbell Newman has broken his promise to seek a ‘‘mandate from the people’’ before selling state assets.

The Newman government has commissioned construction union superannuation fund Cbus to build a $653 million office tower on the riverfront block at 1 William Street.

The Cbus development will serve as the government’s new headquarters.