Ruth Norman had been waiting since she was a teenager for another chance to walk across the bridge her father helped to build.

Yesterday, using a walking stick to steady her, she made the crossing with her niece Aimee Walker.

Exactly 50 years had passed since Mrs Norman and her brother travelled to Auckland from Rotorua to mark the opening of the harbour bridge along with a claimed 100,000 people in 1959.

The difference yesterday was that the 2000-odd protesters who made the crossing had not been granted passage.

They bashed through bushes and jumped fences, and at the beckoning of 23-year-old Erin Allison-Maxwell, who ran in front of the northbound traffic holding his hand out in a stop sign, pedalled and strode past police and motorists and whooped their way towards Northcote - enjoying unobstructed views of the city on a cloudless winter's morning.

Fifty years ago, Mrs Norman was joined by members of her extended family who had made a special trip from the Far North for the occasion.

She was extremely proud of her father, Peta Wairua, one of the men who built the bridge. "It was a wonderful thing at the time."

She remembers some of the kuia crying as the bridge swayed - they had never been on a structure like it. "It was very scary actually, very scary."

Mrs Norman went on to become deputy chairwoman of transport at the Auckland Regional Council, where she campaigned vehemently for a walking and cycling lane across the bridge.

But 10 years ago, the response was always "we are looking into it".

New Zealand Transport Agency regional director Wayne McDonald reiterated yesterday that a walkway or cycleway would not be possible for at least 30 years, after an alternative harbour crossing - an underground tunnel - was built.

He said the agency had made it clear that protesters would not be granted access to the bridge because it was unsafe: "It's illegal to either walk or cycle on the motorway. The bridge is a motorway; it's the law."

Nevertheless, in support of the Getacross campaign, a few thousand walkers and cyclists gathered to demand passage to "their" bridge.

Despite polite pleas and then jeers of "no brain Wayne", Mr McDonald remained deadpan as he reached for the megaphone and repeated "no".

The agency had treated groups like Cycle Action Auckland as "imbeciles" as they sat in their "comfortable offices" making decisions on roading while ignoring pleas for better walking and cycling in the region, Cycle Action leader Bevan Woodward said.

Motorists were far from happy at the disruption. Gordon Sheach, 27, was held up for an hour. "It's funny but it's a waste of time," he said. "They could have been having a game of golf or a coffee or doing something else."

Yasmin Hyde said the march proved many cyclists were "selfish, arrogant and a danger to road users".

"Any sympathy I had for them or their causes has vanished, as I watched the huge piles of cars and frustrated people walking around the motorway - the icing on the cake being a bus and ambulance stuck in the middle of the pile of cars."

However, Councillor Christine Rose, chairwoman of the ARC's transport and urban development committee, told the protesters the bridge needed to be open to cyclists and walkers because "we want a city that burns fat, not oil".

Kelvin Aris, of Living Streets Aotearoa, said: "It's very interesting that there are more people walking than anything else. It would have changed their understanding of what transport is about - it's not just about getting from A to B, it's about the journey."