A new road crossing over the Firth of Forth has been backed by the first minister and the transport minister.
Experts have been studying corrosion in the current bridge
Although the final report into the state of the bridge is due next summer, Transport Minister Tavish Scott has been briefed on preliminary findings.
The study was ordered amid continuing concern about the level of corrosion in cables on the current bridge.
A Scottish Executive spokesman said: "These findings indicated a replacement crossing is required."
The spokesman added: "The first minister has therefore asked for a report to be brought to cabinet.
"This report will cover the new information on options for a replacement crossing, an up-to-date technical assessment on the existing Forth Road Bridge and the further work on financing a replacement crossing."
Green MSP Mark Ballard condemned the executive's backing for the crossing.
"The executive has shown astonishing recklessness," he said.
"Having previously said it would wait until all the research it commissioned had been completed, ministers now appear to have jumped the gun and given the go-ahead for a second bridge.
"Waiting for the final results of the studies would have allowed for informed debate and a decision based on facts, not electioneering."
A Friends of the Earth spokesman said: "If the executive has to replace the bridge then we find that acceptable.
"However, if it results in increased road capacity then it is unacceptable and will undermine all the executive's commitment to stabilising road traffic levels and reducing emissions."
Bruce Crawford, mid-Scotland and Fife SNP MSP, said: "Construction must be ready to start so we can remove any risk of a period of closure, with the devastating effect that would have on the economy of Scotland and in particular the economy of the east coast and north of our country.
"The Forth Road Bridge is an essential artery for transport throughout east and central Scotland.
"Closing or restricting this route would impact on each and every alternative North-South route and create substantial difficulties, not only for businesses based on either side of the Forth but many major businesses in Scotland. That is unacceptable.
"This is the right decision for Fife and for all of Scotland."
Louise Batchelor, BBC Scotland's transport correspondent, said the new crossing might not be a bridge and may also be used by trams.
She said: "The Scottish Executive hasn't got down to the detailed plans. There still could be a tunnel, for example, so for the time being it is a crossing, which also may or may not be just for cars."
In November last year a full independent assessment of the state of cables on the Forth Road Bridge was commissioned after initial inspections by the Forth Estuary Transport Authority (Feta) found some corroded cables on the bridge.
It said that unless action was taken the 42-year-old bridge could close to heavy goods vehicles by 2013.
Campaigners have said a new road crossing would help reduce congestion and stimulate the local economy.