Traffic delays are expected due to emergency repair works being carried at the York Place/Station Parade junction in Harrogate.
Contractors are currently on-site and work has started to repair the collapsed manhole chamber.
It is anticipated the works will be completed late this afternoon or early evening.
However, the lane has to remain closed until the concrete chamber has set and temporary traffic lights will now be in place until tomorrow.
A spokesman for North Yorkshire County Council said: “The county council’s area highways office investigated a report of a loose manhole cover at the York Place/Station Parade junction and found the fault was with the underground structure supporting the cover.
“This was deemed to be unsafe and had to be repaired as an emergency, particularly given its position in the centre of the carriageway.
“The site will be inspected in the morning and the traffic management will be removed as soon as it is safe to do so.”