Scottish Water has said they expect the closed section of the A96 Inverness to Aberdeen road in Moray to now not be reopened until Saturday.
Bear Scotland is working closely with the agency to get the repairs near Lhanbryde, east of Elgin, completed.
The road was originally due to reopen on Thursday, however, this was pushed back to Friday to allow time for the tarmac to dry thoroughly.
Scottish Water has now said they expect the road at Threaplands to be closed until Saturday.
The extent of repairs and the need to “meet specific structural requirements” on the section of the carriageway has resulted in work taking longer than hoped.
The road between Lhanbryde and Mosstodloch has been closed since Tuesday for Scottish Water to fix an underground water pipe leak.
It is understood the burst water main has eroded soil underneath the road with signs of “sinking” evident on both sides of the carriageway.
A 10-mile diversion is in place along the B9103 and B9105 via Inchberry.
A Scottish Water spokesman said: “We would like to apologise for the delay to the re-opening of the A96, which is a result of the standard and extent of reinstatement that is required.
“Our team’s focus, supported by colleagues from Bear Scotland, is on completing the repair and full reinstatement of the road as quickly and safely as we can while ensuring that there is minimal risk of disruptive remedial work being required in the future.”
He reassured motorists that the diversion route is being managed by contractors and has operated “smoothly”.
The spokesman encouraged road users to allow extra time for journeys and to consider alternative routes where possible.