According to Nine News, the owner had complained that the device was not holding a charge and was just about to hand it over to the shop owner when it began to emit smoke.
The iPhone 6 Plus starts emitting smoke just as it is being handed over.
CCTV footage of the incident, put up on YouTube by a user who goes by the moniker ViralHog, showed the iPhone 6 Plus emitting clouds of smoke and the shop owner having to use a fire extinguisher to prevent anything more untoward happening.
Nine quoted ViralHog as saying the explosion blew the screen off the phone and the shop could not be opened for the rest of the day due to the fumes.
ViralHog claimed the following was what happened at the store.
"A customer came into the store with a screen-damaged iPhone 6+ for repair. The customer wanted repair of the broken screen and complained about Apple's genuine battery not holding charge.
"We removed the customer's Otterbox and prepared to book the phone in. Then, the customer picked up the phone and applied a regular amount of pressure to the screen, the same as any normal person would do everyday during regular use.
Toast: The iPhone 6 Plus after the incident. Note the misshapen battery.
"The battery failed and exploded. Initial force of the explosion caused the screen to come off the phone.
"Our staff extinguished the phone with a fire extinguisher. We had to evacuate the store due to fumes and could not open for the rest of the day."
Last year, an iPhone 7 Plus was reported to have exploded while in transit.
The best-known case of mobiles exploding is, hower, that of the Samsung Galaxy Note7 which had to be yanked from production last year after numerous reports of explosions.