Watt Street in Newcastle East will stay closed for two weeks longer than expected.
Crews upgrading the road surface between Church and Scott Streets ahead of the Newcastle 500 were hoping to re-open the road this weekend but the discovery of an old water main and stormwater main means re-opening will now happen mid-September.
Event Manager Kurt Sakzewski says it's disappointing - but it's important the area is made safe.
"It's unfortunate as we get so close to the end of the Watt Street works that something like this comes up."
"Unfortunately it does happen from time to time, and it's been quite a while since anyone's dug up Watt Street so these types of surprises can happen."
Meantime plans to re-route bus services along Watt Street while light rail construction takes place on Hunter and King Streets has been delayed.
Bus routes now won't change until September 10.