Despite having the chimney regularly cleaned, it appeared something had blocked it. Mrs Poszeluk suspected a birds' nest.
"It had spewed out the top, which is what caused [the fire]."
The fire service was at Jarks for about 40 minutes making sure the fire had not spread.
"As a tenant we had to ensure everything was absolutely clear from any risk," the owner said.
With a full house booked for lunchtime, Mrs Poszeluk said she was happy they could get things up and running again.
No damage could be seen from outside and inside the building was abuzz with chatter from happy diners.
Jarks used to be located in Waimarama before they made the move to the city to broaden their seasonal service, Mrs Poszeluk said, and they now enjoy the bustling environment at their Maraekakaho Rd address.