A stretch of the A83 which reopened for a period on Wednesday after a landslide at the weekend has been closed again because of heavy rain.
One lane of the road between Cairndhu and Arrochar had been opened for eight hours and work had taken place to prop up ground on the hill above the road.
But a spokesman for maintenance firm Transerv said more rain had created a greater risk the land could slip again.
The road will not now reopen first thing on Thursday as had been planned.
It was closed between the A814 at Arrochar and the B828 after 400 tons of soil and rock, loosened by several months of rainfall, tumbled down onto the road overnight on Sunday. No-one was injured.
After work by geotechnical staff, it had opened between 0800 GMT and 1600 GMT on Wednesday and was due to reopen at 0800 GMT again on Thursday.
A landslip at the same place three years ago led to the road's closure for a couple of days.