Transport bosses have accused protest leaders of breaking their word by encouraging people to flout the law and storm across Auckland Harbour Bridge.
The bridge has been officially opened to pedestrians only once when it was built 50 years ago.
Today protestors wanted to go over again to demand a walk and cycleway.
"When the tunnels are built under the harbour side the load on this bridge can be taken off," says Wayne McDonald from the New Zealand Transport Agency. "Then there will be walking and cycling on this bridge, but that's probably 30 years away."
But the crowd weren't ready to wait that long and thousands of people poured out in front of motorway traffic, bringing the northbound lanes to a crawl for more than an hour.
With 20 officers facing thousands of people, the police were powerless to stop them. Instead they raced to flag down the traffic that was hurtling at 80km/h around a bend towards the bridge.
And at the bottom of the bridge, stranded drivers were forced to wait and watch.
One man didn't make it over was protest organiser Bevan Woodward. He says the protest wasn't intended to disobey police and force their way onto the motorway.
The Transport Agency says it has learned lessons from today's actions and will beef up security for the next time anyone plans a protest.
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