WORK could take several months to repair the main road between Helston and Penzance, Cornwall Council has warned.
The westbound lane of the A394 Helston to Penzance road has been closed for a 100m section near Little Antron Farm, about two miles west of Helston.
This happened on Friday after the discovery of large cracks in the carriageway, thought to have been caused by the floods which affected many areas across Cornwall in December.
A spokesman for the council, which is the highways authority, said engineers were now carrying out further investigations into the damage to identify how best to repair the road.
On Monday, the spokesman said: "It looks like the section of the carriageway could be closed for several months, but this all depends on the extent of the damage and the results of the surveys."