POLICE say the Old Shoreham Road could be closed for up to three days while engineers repair a burst water main.
Up to 80 homes could lose their water supply while repairs are carried.
Police closed the road in both directions this afternoon, between the Clover Leaf roundabout and the Red Lion pub, at the junction with Upper Shoreham Road, over concerns the road was collapsing.
Initial plans to install three-way traffic lights to control traffic have been scrapped and the road could now remain closed until the weekend.
A Southern Water spokesman said: “We’re repairing a six-inch water main on the A283 Old Shoreham Road that burst earlier today.
“Part of the road, near the Red Lion pub, has been closed so we can carry out the repair safely.
“Up to 80 properties are likely to lose their water supply, or have low water pressure.
“We know traffic is already heavy in the area and we are doing all we can to fix the main, restore water supply and reopen the road as quickly as possible.
“We’re sorry for the inconvenience.”