Smoke is seen coming from the SkyCity Convention Centre after a fire broke out on the roof top on October 22, 2019 in Auckland, New Zealand. Construction workers were forced to evacuate after a fire broke out at the top of the $700 million SkyCity Convention Centre in Auckland's CBD. Photo: VCG

A massive fire at the Auckland venue being built to host the 2021 APEC forum raged for a second day on Wednesday, as New Zealand officials insisted the event would go ahead.

The blaze broke out at the SkyCity convention centre construction site on Tuesday afternoon and was still blanketing the city with smoke a day later, despite the efforts of more than 100 firefighters.

Deputy Prime Minister Winston Peters conceded the centre was "extraordinarily unlikely" to host leaders from the 21 Asia-Pacific Economic Cooperation (APEC) forum nations in November 2021 as scheduled.

But he said New Zealand's largest city would still hold the annual summit, which is being staged in the Chilean capital Santiago this year.

"We won't lose APEC. We are a big enough country to run it without the convention centre," Peters told the New Zealand Herald.

"Auckland has got some alternatives. I don't want to jump in to say what they are, although some of them will be obvious as venues ... which are capable of the security and the least amount of interruption."

When APEC was held in Papua New Guinea last year, cruise liners were used to accommodate delegates due to a shortage of hotel rooms in Port Moresby. 

The NZ$700 million ($450 million) centre, being built next to the distinctive SkyCity tower and casino complex, was New Zealand's largest construction site.