The A18 Mountain Road is now closed until no later than 6am tomorrow (Tuesday) to allow for 'essential safety works' to take place.
It closed at 6.30pm tonight (Monday) between Barrule Park, Ramsey and the Bungalow (Tholt Y Will Road junction).
The works are necessary for Department of Infrastructure contractors Paul Carey and Sons to complete the project they began after a fall of materials onto the carriageway near the Waterworks over the Christmas period.
The landslide resulted in the DoI having a roadside wall built to catch any further loose material before it reached the road.
The DoI said: 'As part of these works the Department’s contractor, Paul Carey and Sons, has been working for the past couple of weeks to remove the overburden (soil and loose stone) from above the rock face at this location.
'It is intended that this work will reduce the likelihood of a similar fall occurring in the future.
'It had been planned that all works to remove the overburden would be achieved without the need to close the road below the worksite.
'This has been reassessed in the light of local conditions and it has been decided that for the final part of this work, traffic and pedestrians will be prohibited from travelling on the road whilst works are completed on safety grounds.
'The team undertaking these works will be working overnight using floodlights in order to mitigate the overall impact on the public.
Arrangements are in place to pause work and allow emergency service access past the site should the need arise.'