Brisbane's Story Bridge will have three metre-high safety barriers in place by mid 2014, Lord Mayor Graham Quirk announced on Wednesday.

The Lord Mayor explained council's decision privately to journalists and then issued a statement saying he did not want to discuss the issue publicly.

The total plan includes a three metre-high curved fence on the outer edge of the Story Bridge walkway.

Protective mesh will cover the horizontal gap between the roadway and the actual walkway on both sides of the bridge, which are now open.