Drivers trying to avoid queuing at exits on the Auckland Harbour Bridge should be wary of using bus lanes - the police are watching.

Sergeant Helen Faith of the Ellerslie Motorway Patrol confirmed an officer was stationed just past the Shelly Beach Rd exit filming motorists using the bus lane.

The officer was on a corner near the Fanshawe St exit where the inside bus lane ends and merges with the rest of the traffic.

Mrs Faith said the area had become a problem in peak times when motorists tried to avoid congested lanes near off-ramps by travelling in a bus lane.

"We get complaints now and again from drivers who are doing the right thing and queuing. This kind of thing creates road rage which is why we are trying to put a stop to it," said Mrs Faith.

She could not confirm how many drivers were snapped in yesterday's bus-lane blitz - but said they would be in for a $150 fine.

The police would not say if this would become a regular event.

AA Spokesperson Simon Lambourne said motorists should obey road signs at all times to keep the motorways safe and ensure traffic flows smoothly.

Mr Lambourne said drivers using the T2 lanes on motorway on-ramps to avoid queuing at ramp signals was also an issue.

The T2 lanes are reserved for vehicles with two or more passengers - and in most cases, bicycles, taxis, emergency vehicles and motorcycles as well.