Jacinda Ardern supports cyclists closing two lanes of Harbour Bridge in protest, but condemns breaking through police barricade to do so

Prime Minister Jacinda Ardern says she supports frustrated cyclists who closed two lanes of the Harbour Bridge, but says they shouldn't have broken through a police barricade to do so.

On Saturday a 'Liberate the Lanes' rally was held at Point Erin Park below the bridge, calling for a three-month trial of a cycle lane.

After the rally, hundreds of cyclists forced their way onto the Bridge through a police barricade.

The northbound lanes were closed for two hours as a result.

Speaking to The AM Show on Monday Ardern says she agrees the North Shore needs to be connected to Auckland city, via modes of transport other than buses and cars.

"You'd be hard pressed to find people who don't support that."

Ardern says the Government is working to provide a solution but there's been several setbacks.

A long-planned cycling and walking path across the Bridge, Skypath, suffered another setback in March when technical issues surfaced. Transport Minister Michael Wood said at the time it hadn't been cancelled, just delayed.

Ardern says the same thing.

"Engineers have come forward and said perhaps attaching [Skypath] is more problematic so we have to find another way, but I'm not against people finding other modes of transport."

But cyclists don't want to wait any longer. 

Bike Auckland deputy chairperson Duncan Laidlaw says all they're asking for is a three months trial of a cycle lane over the bridge.

"People have been waiting for decades - it's now 12 years on from the first protest asking for a cycle lane."

Both Laidlaw and Ardern stopped short of endorsing protesters breaking through the barricade however.

Ardern says it's her job to keep people safe - so breaking through a police barricade is not something she can support.

"I understand their frustration but I am in a position where if someone was hurt we would be having a very different conversation."

Laidlaw says while he agrees with the right to peaceful protest, he was not involved with the barricade break through whatsoever. 

Police said they were "disappointed" by those who breached the cordons and one person who initially breached the cordon was arrested and is being spoken to.

No injuries were reported.