Outrage over Greenpeace boss Russel Norman's bitter tweet about SkyCity fire

A former politician has been blasted on social media for posting a sarcastic tweet about the fire in Auckland's CBD.

Russel Norman, former leader of the Greens and current executive director of Greenpeace, posted on Twitter about the blaze destroying the SkyCity Convention Centre.

"Always said John Key's convention centre deal stank," wrote Norman on Tuesday.

"Today it stinks of burnt plastic, right across Auckland CBD."

The fire began on Tuesday afternoon and has blazed incessantly for close to 24 hours. Auckland's CBD has ground to a halt due to multiple road closures and toxic smoke billowing across the city.

One person has been hospitalised and four others were treated for minor injuries at the scene.

Norman's post received swift backlash, with many people calling him "nasty" and saying the post was inconsiderate.

"That Tweet is totally uncalled for and nasty think of the first responders and people trying to get home," wrote Twitter user.

"Wind your neck in" said another.

"Delete this you prize pillock," said another angry woman.

Norman's tweet references the controversial timeline of the SkyCity convention centre under former Prime Minister John Key's leadership.

Plans for the convention centre were laid in 2011 by Key.

The $470 million centre began construction in 2016 after years of negotiations about gambling regulations.

 By 2018 Fletchers Construction announced the expected loss on the building was a staggering $660 million - $500 million more than anticipated.

Originally expected to be finished by February 2019, it was announced in November 2018 the building would not be finished until "beyond December 2019".