A pod of orcas, including a visitor last seen 13 years ago, stopped traffic and delighted ferry passengers as they weaved their way across Auckland's harbour yesterday.

Eight orcas, including two calves, swam into the Waitemata Harbour past North Head at 11am.

Maritime advisor Brenda Orr from the harbourmaster's office said the killer whales came as close as 20 metres to the shore near Mechanics Bay.

A crowd of motorists on Tamaki Drive stopped to watch them swim further up the harbour.

The orcas' sail-like dorsal fins were then seen close to Princes Wharf before they swam under the harbour bridge.

A group of kayakers gathered to watch them chase fish near Pt Chevalier.

Orca Research Trust founder Ingrid Visser said one of the adult whales was identified as "Corkscrew" - an orca known for his twisted dorsal fin. It was only the third time he had been spotted in the North Island, and the first time in 13 years.

She said the whales had come into the harbour to feed, stingray being a common prey.

"Orca can turn up any time, anywhere around New Zealand but it's more typical for them to be around this time of year."

November is the end of the orca season, when they come close to shore to feed.

Fullers ferry service spokeswoman Lucy Farrington said yesterday she expected the orcas to leave with the tide that evening, providing a spectacle for commuters on their way home.