The increased number of lorries heading for Cairnryan prompted Operation Overflow to be activated with traffic being “stacked” at nearby Castle Kennedy.
About 500 vehicles have used the facility but Transport Scotland said the situation had eased by lunchtime on Monday.
Officials said there were no issues currently being reported but the situation was being watched closely.
Police also issued a warning to drivers to allow extra time for their journeys due to the rise in HGV usage.
Repair work is ongoing at Holyhead – which is the main sea route between north Wales and Dublin – after damage caused more than a week ago.
On average, two million passengers use Holyhead a year and about 1,200 lorries and trailers make the crossing every day.
Extra ferry sailings have been arranged at Birkenhead, Fishguard and Heysham while it remains out of action.
