Completion of the Â£1.35 billion replacement for the Forth Road Bridge has been put back by bad weather.
The news follows the opening being delayed from last December because of strong winds hampering progress.
Mr Brown is due to announce when the bridge will open to a Holyrood committee at 9:30am tomorrow.
The minister was responding to a question from Mid Scotland and Fife Conservative MSP Murdo Fraser.
Mr Fraser tweeted: "New Queensferry Crossing was promised by FM [First Minister] for end 2016. Then end May 2017. Now delayed again. Very disappointing for constituents."