Several fire engines were called to the building, on the corner of Hobson St and Victoria St West.
Large plumes of black smoke could be seen pouring out of one of the ground-floor premises.
The Denny’s 24-hour restaurant is on the upper level, with Raviz Indian Eatery, Chill and Grill and Daikoku convenience store on the ground floor.
Firefighters wearing breathing apparatus were seen entering the building about 7.45am.
Firefighters secure the perimeter and redirect traffic as they respond to a fire in the central city during Auckland's morning commute. Photo / Anna Heath
Fire and Emergency shift manager Lauren Sika told the Herald that crews from six Auckland stations responded to the fire, including a specialist unit from Glen Eden.