Fire and Emergency crews were called to The Shroom Room on London St just before 8pm, arriving to find the building well ablaze, with flames punching through the roof and thick grey smoke billowing across the neighbourhood.
The fire is believed to have started in the kitchen of the vegetarian/vegan friendly cafe before rapidly spreading through the roof.
Crews from Lyttelton, Sumner and Woolston battled the blaze, bringing it under control by 8.40pm.
The cafe was closed at the time and no-one was inside.
No injuries were reported.
Co-owner Richard Leech said the fire appeared to have started in the front-of-house part of the cafe, although no-one was there at the time.
He and co-owner Koryn Hope were holidaying in Abel Tasman when the fire broke out but were heading back to Christchurch on Monday to assess the damage.
"We're just devastated. It's devastating for our staff and for customers and for us," Leech said.
"It's been completely gutted. Everything is gone."
Leech understood the fire had resulted in some smoke damage to a neighbouring bookshop but no structural damage.
- Allied Media
