The tunnel carries the A58 Leeds inner ring road under the Leeds General Infirmary and is one of the busiest stretches in the city.
Essential concrete repairs have been carried out to the tunnel roof by the contractor AE Yates Ltd on behalf of the council.
The works were carried out over a series of weekends.
Council employees and staff from AE Yates Ltd worked from Friday evenings right through until Monday mornings on a shift system to complete the work as quickly as possible and minimise disruption to motorists.
Councillor Richard Lewis, Leeds City Council executive member responsible for city development, said: “This was a complex and critical scheme and I’m delighted that it has been completed early with the minimum of disruption to motorists. It is thanks to the hard work of all those involved and effective partnership working with the contractor.”
The city council warned earlier this year that parts of the inner ring road could close unless millions of pounds is spent on structural repairs.
The council submitted a bid to the Government this month for further essential repair and strengthening work to the tunnel, as well as to New York Road Viaduct Eastbound and Lovell Park Road bridge. If the bid is successful further tunnel work will be carried out in 2013/14 and 2014/15.