This morning's severe congestion in Auckland is being described as another example of the vulnerability of the city's motorway system.

Commuters faced long delays getting into work this morning on the North-Western Motorway, with city-bound queues backed up past Hobsonville.

Transport Blog editor Matt Lowrie says traffic backlogs have happened before and they're bound to happen again.

"That's why it's really important we provide high-quality alternatives - things like the Northern Bus way and the rail network."

The so-called annual "March madness" is now well underway on Auckland roads.

Matt Lowrie says there are more people on the roads, but there are also more people using public transport.

"There are lots of people using public transport, and we're already seeing buses and trains packed and people occasionally being left behind."

Mixed review for weekend transport

There have been mixed reviews for public transport during what's being called Auckland's busiest weekend on record.

The Cricket World Cup, Volvo Ocean Race, Lantern Festival and Ellerslie races attracted hundreds of thousands of people to the inner city.

But many people complained of full buses and long delays for services.

Matt Lowrie says public transport was excellent on Saturday night but extremely poor on Sunday night.

"There weren't any extra services on for the Lantern Festival, so there were not trains on when it finished and buses were very infrequent."

The events caused rush-hour traffic and public transport delays on Saturday night.

But an Auckland Transport spokesman says extra services were put on to accommodate the events and many services were nearly empty.