A full independent assessment of the state of cables on the Forth Road Bridge has been commissioned by Transport Minister Tavish Scott.
A full assessment of the bridge has been ordered
Initial inspections by the Forth Estuary Transport Authority found some corroded cables on the bridge.
It said that unless action was taken the 41-year-old bridge could close to heavy goods vehicles by 2013.
Mr Scott said he would receive advice in January which would allow detailed consideration of the options.
No safety concerns
He assured motorists that the bridge was entirely safe to take traffic.
The transport minister said: "It is clear there is indeed some corrosion and further work will now continue into the extent and possible remedial action.
"I have asked for an independent assessment of FETA's emerging findings and a full engineering technical study into the condition of the bridge cables."
The full engineering study should be completed by summer 2007.
A spokesman for FETA said: "There are absolutely no safety concerns for people who use the Forth Road Bridge.
"We are still waiting on our consultant's report on the main cable and an update will be presented to our board later this month."
Scottish National Party MSP Bruce Crawford said: "MSPs have been warning the executive for some time now that they must start planning for a new bridge across the Forth.
"I hope this report from FETA gets the alarm bells ringing loudly in the executive's ears. Ministers must now make the building of a new bridge a top priority for the National Transport Authority."
"There is no room for complacency and action must be taken now to ensure that the bridge continues to be a safe and reliable link to the east of Scotland."
Scottish Conservative Transport Spokesman David Davidson said: "Whilst I welcome the fact that the minister has taken this step, I am exasperated by the executive's foot-dragging on the need for a replacement crossing."