"It literally just exploded," a bystander told The New Zealand Herald.
"You've got glass exploding at the busiest food court in town."
There was no warning of the glass pane imploding at O'Connells Shopping Centre, believed to be caused by scorching temperatures in the city.
Two people with what looked to be minor injuries were treated by St John ambulance and police also arrived to cordon off the area as shards of glass were swept up.
People were forced to shake broken glass off their clothing after the accident, which happened around 5.30pm this evening.
A witness said around 10-20kg of glass littered the streets, crunched by the feet of hundreds of pedestrians out on New Year's Eve.
A bystander said the shopping centre building was due for refurbishment and that the glass might've been in the building for "quite a number of years".
Police have been contacted for comment.
