Emergency services battled a fire in No7 Balmac's ventilation system on Saturday.
Business owner Katrina Toovey walked through the premises with experts yesterday and said it would be about three months until the restaurant could reopen.
``It's unfortunate things can't go as quickly as I would like.''
It would require a new ventilation unit and new floors where they were water-damaged.
There was a ``pretty incredible'' response from the public after the fire, she said.
``Sometimes when you have your head down in business you don't realise you are important to people, so that's been really nice.''
The fire occurred on the day of University of Otago graduations, and many parties had booked the restaurant for their celebratory dinners.
They were given the offer to dine instead at the Esplanade restaurant, in St Clair, which Ms Toovey also owns.
It was ``really lucky'' Esplanade did not take bookings, but switching them over was a challenge for her staff, she said.
``It's obviously not ideal, because a lot of people had to be turned away.''
The break would be a good time to see if any changes could be made to the establishment, she said.
The chimney in which the fire started was on a cleaning schedule and everything was up to date, she said.
Fire and Emergency New Zealand fire investigator Mark Bredenbeck said the fire started within the extraction flue which serviced a wood-chip grill.
This led to surrounding timbers and the service duct catching fire, which spread through the ceiling space.
He was still investigating exactly why the fire started, he said.
There was some water damage from fire-fighting efforts and from a water pipe which burst in the fire, he said.
``It's just one of those things that happens. There are no immediate lessons until we know exactly what has occurred.
``But again, because we know it occurred in a chimney, I guess it's a timely reminder to keep your chimney clean.''
