Salsa Moves is the latest business to move into the partly-restored building.
About 145 staff from Silver Fern Farms started work in their new headquarters on the first two floors of the building on March 25, and Multipeak Fitness hopes to open a gym on the second floor by mid-May.
Salsa Moves owner Alfonso Rios said New Zealand was full of dancing talent which was just waiting to be tapped into.
''I find when people get over their self-consciousness, they have fun and they begin to dance.
''New Zealanders don't know how good they can dance. I'm here to help them unleash the dancer within.''
The Latin dance studio, formerly in South Dunedin, has about 100 members. But Mr Rios hoped once the studio was settled in its new premises on the second floor, membership would grow to about 200.
Salsa Moves is subletting part of Multipeak Fitness's premises, and Mr Rios believed between the two businesses, the second floor would become a one-stop health and fitness shop.
''There will be a gym, physio, massage, aerial jogging, Pilates, Zumba and Latin dance. We're looking at having meditation classes, too.
''There's a lot happening here.
''I've been dreaming of something like this since I arrived in Dunedin 11 years ago.
''It's basically a health centre.''
Mr Rios said Salsa Moves would officially open in the chief post office building on Saturday, with three dance sessions.
One of Australia and New Zealand's greatest Cuban female Latin dancers, Greydis Montero, would perform at the opening, he said.