Emergency services were called to Pumice cafe on Church Road just after 7am to find the building well involved in flames.
Six appliances responded to the blaze, northern fire communications shift manager Paul Radden said.
It took fire crews about three hours to get it under control.
Photos of the building remains have been posted on the cafe's Facebook page.
A post on the page read: "Devastating stuff to come back to ..... Pumice will be closed till further notice."
More than 20 people had posted replies of support and condolences, including one from Glenn Stanbridge who wrote: "Very sad! Sorry for your loss! Looking forward to an even better pumice to emerge out of the ashes!"
The owner, David Kerr was not immediately available for comment.
- Rebecca Quilliam of APNZ
