The gym on Auckland's North Shore where the New Zealand Breakers secured the Australian National Basketball League title last Friday is being converted temporarily into a haven for those left homeless by today's tornado.

Civil Defence said the North Shore Events Centre in Glenfield would be turned into an emergency welfare centre for people displaced from their homes by the tornado.

Work and Income, Victim Support and the Salvation Army would be assisting. Anyone needing assistance should call 0800 463 010.

A spokeswoman for Auckland Council said it was unclear exactly how many people had been displaced.

The Breakers' owner, Paul Blackwell, also had his main business hit by the tornado.

Mr Blackwell owns Albany Pak n Save, which was evacuated following the tornado.

Murray Jordan, the managing director for Foodstuffs, which franchises Pak n Save stores, said the evacuations of both Pak n Save and the nearby New World went smoothly, with no customers or staff injured.

Mr Jordan said initial reports Pak n Save had significant damage were incorrect, saying it only had superficial damage, while New World had next to no damage.