Three northbound lanes were closed while emergency services attended the scene of the crash.
Auckland motorists were stuck in grid-locked traffic, making a normally 40-minute journey from the airport to the North Shore take up to three hours.
The tail of the traffic jam on State Highway 1 stretched from the base of the Harbour Bridge to Highbrook Drive, Otahuhu, before all lanes were re-opened at 3pm.
Traffic on the Northwestern Motorway was very heavy, with motorists diverting trips they'd usually take on the Northern Motorway in an attempt to avoid the snarl up.
Roads throughout Central Auckland were also backed up as motorists tried to get on the motorway and became stuck.
Traffic build-up following the incident on the Harbour Bridge. Photo / Jason Dorday
Dan Boyd had flown to Auckland from Wellington with his wife, who got her first taste of the notorious Auckland traffic.
"It was an eye-opener for her, for sure."Mr Boyd and his wife have relocated to Devonport and spent the first three hours in their new home stuck in the car.
"I actually got sunburnt, because I never thought I was going to be in the car that long and didn't put sunblock on. So I'm red as a beetroot, but just one arm."
North Shore man Brendan Thompson said it took him about four hours to drive from Sylvia Park to Albany - with three unhappy children in the car.
"By the time we got home they'd nearly killed each other and I was at my wit's end. It was a hell of an afternoon," he said.
"I can't believe that one accident on a bridge can stop a city. You'd like to believe that the country's major city could get the traffic flowing quicker than that."
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Spokesman for New Zealand Transport Agency (NZTA) Ewart Barnsley said traffic on the motorways was heavier than normal today.
"There were a couple of events in town... and you've got to take in to account Christmas shopping," he said.
Mr Barnsley said four sites of roadworks to widen the Northwestern Motorway and the work on the Waterview Tunnel contributed to the slow crawl on the Northwestern Motorway.
North Shore resident Jillian Ewart said her journey home to Mairangi Bay from Ponsonby took her one hour 15 minutes, when it would normally take 20 minutes.
She said the snarl up showed the vulnerability of having just one harbour crossing.
One of the motorcycles involved in the incident. Photo / Victoria Young
"It's just ridiculous that they're spending so much money on the rails going south... if it had been a really major event [the Harbour Bridge] would have been out for days not hours."
Labour spokesman for transport Phil Twyford said the traffic jam caused by the crash showed the lack of resilience in Auckland's transport system.
"The mega traffic jam is a sign that something's not right in our system."
Mr Twyford travelled into the city on the Northwestern and saw first-hand the slow crawl caused by all the motorists diverting from the Southern Motorway.
"It was like a giant parking lot... Cars were hardly moving at all."
He said it showed the value of investing in rapid transport systems like the City Rail Link.
Transport commentator Matt Lowrie, of transportblog.co.nz, said no number of new motorways - even another harbour crossing - would prevent congestion like yesterday's after serious crashes at key pinch-points like the Harbour Bridge.
"There's very little that can happen when those sorts of accidents occur. What we can do is build a congested free option - more public transport or walking or cycling - so that people do have an alternative."
Police said the motorcyclists appeared to be wearing gang patches. The Head Hunters held their annual Poker Run yesterday in Silverdale.
