Otago Daily Times reporter Chris Morris said it had taken him 50 minutes to drive from Burkes to Ravensbourne, a drive that would usually take less than 10 minutes.
The disruption was caused by roadworks in the 70km zone between Ravenbourne and Forsyth Barr Stadium.
The bottleneck has eased and traffic is now flowing.
NZTA Senior Network Manager John Jarvis apologised for the delays road users encountered this morning, and said the agency was taking steps to ensure they were not repeated.
The soft ground conditions meant traffic was unable to drive much over 5kmh, causing long traffic queues.
"When removing old asphalt, you can never be totally sure of what ground conditions you will find and that is what has occurred on this section of road at 6am this morning."
Motorists could expect delays of 7-8 minutes on the road this afternoon due to the uneven surface.
Mr Jarvis said minor work was being carried out today on the traffic lane to Port Chalmers between the Parry Street roundabout and Ravensbourne so it could handle traffic at speeds of 50kmh by 3pm this afternoon.
However, because of the amount of traffic around with a cruise ship in Port Chalmers, delays of up to 10 minutes were still possible.
"We suggest road users allow up to 20 minutes extra travel time at peak times."
Overnight, the focus will be on getting the Port Chalmers to Dunedin lane up to the same standard, so road users do not experience lengthy delays tomorrow morning.
The resurfacing work is expected to be completed next Wednesday.
