The cost of renting Queensland ministerial office space has almost doubled, with taxpayers expected to fork out more than $10 million next year.

Since moving to the privately owned 1 William Street, ministerial office rent has almost doubled from $5.07 million budgeted in 2015-16 to $10.2 million in 2018-19.

1 William Street in Brisbane. Credit:Ruth McCosker

The 260-metre-high "tower of power", or "Big Willy" as it is known by some, was built for $650 million, with developer Cbus footing the bill, after it was commissioned by the former Newman LNP state government.

However, the arrangement has come at a large cost for taxpayers.