The westbound carriageway of the underbridge near junction 23 into Llanddulas is set to be closed for five weeks.

Essential works, which will include surface removing; waterproofing of the bridge deck; and the replacement of bridge joints, will begin on September 17 and will run through until October 18.

This work requires a full closure of the westbound carriageway in the area with a single lane running traffic in both directions all day and night for up to five weeks.

The waterproofing needs to be laid in reasonable weather conditions which is why it has been programmed to take place during this period.

Similar works on the eastbound carriageway are set to take place later next year.

Transport secretary, Ken Skates, said: “I have been absolutely committed to ensuring there have been no routine daytime lane closures on the A55 from the English border to Junction 11 from April 2017 until September 2018 and I am delighted we have delivered exactly that.

“During that period, resurfacing long lengths of the A55, repairs and maintenance, including to the route’s tunnels, have all been carried out overnight resulting in very little disruption to traffic.

“I want to thank officials, contractors and all those involved in planning these works who continue to work tirelessly to ensure the smooth running of this key route.

“We have also been carrying out night time works on the Kneeshaw Lupton underbridge near Llanddulas to keep in use the temporary repairs we have previously put in place on the structure.

"We do however need to carry out permanent repairs as the bridge deck itself is now showing signs of distress. I have to reiterate this is essential work which must take place.

“I fully understand that roadworks during the daytime can cause disruption, but they need to be carried out on all major roads to ensure the safety of the travelling public and strengthen a route’s resilience.

"These are matters on which I will not compromise.

"We have also taken action to offset the impact for the travelling public by ensuring work on the eastbound carriageway can be delayed until next year.

“I ask the travelling public for their patience whilst this work is carried out and it will be on a 24 hours a day, seven days a week basis at pace so it can be completed as quickly as possible.”