The fire, which started on Tuesday afternoon, is believed to be ignited by a torch used to heat and seal waterproofing materials on the roof of the building under construction as the scheduled venue for 2021 APEC meetings, Xinhua news agency reported.
Local fire emergency department worked round the clock to control the fire, but had to sacrifice the roof to allow crews better access to the fire. The fire continued overnight with flames and heavy smokes seen across the city.
It is unknown yet how the fire has destructed the building, which was due to be finished by August or September next year.
Auckland Mayor Phil Goff said on Wednesday morning that the fire could impact the APEC conference in 2021, but will not jeopardize Auckland as the event's host city.
Civil defence department issued an emergency alert on Tuesday night to mobile phones across Auckland. Public health officials are advising members of the public to stay away from the CBD and out of the smoke.
Traffic in the Auckland CBD was diverted with multiple road closures and several nearby office buildings were closed due to safety concerns.
It is unknown how long the fire will continue as the roof contains inflammable materials.
Severe gales and rain is forecast for Wednesday afternoon.
( With inputs from IANS )