A Fire and Emergency NZ spokesperson said two appliances were called to the New Brighton Burger Bar on Shaw Ave about 1.30pm.
A section of Shaw Ave was closed until about 3pm as crews worked to extinguish the blaze.
They managed to prevent the flames from spreading to the neighbouring shops.
ANZAC station officer Tony West said the flames were coming out the shop windows when the fire crews arrived.
West said the cause is being investigated.
No one was injured in the fire but the shop was badly damaged.
A spokesperson for Hangi House across the road said: "A hardworking business across the road from the Hangi House has caught on fire in The Gateway of New Brighton.
"The Hangi House will be open this week from Wed-Sunday and we will also be going over to Kim’s Burger Bar to help with clean up and see if they need any help in the next week.
"These events are unfortunate but with a bit of support - they will be up and going before we know it and back into it."
