Ms Sullivan has leased the ground floor from the Oamaru Whitestone Civic Trust and will open The Loan and Merc later this year.
The premises were previously occupied by Prestons Associates Ltd, now in receivership.
The trust served an eviction notice in February because of rent arrears.
Ms Sullivan established the popular seaside restaurant Fleur's Place in Moeraki in 2002 which marked her return to the restaurant trade after about five years.
She previously owned Olivers, at Clyde.
Fleur's Place has become a focal point in the fishing village and attracted some high-flying clientele, including actress Gwyneth Paltrow and her then boyfriend (now husband), Coldplay singer Chris Martin, and British television chef and restaurateur Rick Stein.
The Loan and Merc would be "entirely different" to Fleur's Place.
It was an exciting venture based on the principles of the slow-food movement and "totally in harmony" with the building, Ms Sullivan said.
It would be another "jewel in the crown" of the area, continuing the aspirations of both the trust and the former tenants, Warren and Debbie Preston, she said.
She hoped to open the business on November 1, in time for the town's annual Victorian heritage celebrations.
Trust chairman Phil Hope expected it to be a significant drawcard.
The building was well sited near the new Wansbeck St extension and would be a focus for cyclists finishing the planned Alps to Ocean cycleway.
It would make the precinct more vibrant without, in any way, detracting from the historic aspects of the building or the area, he said.
Negotiations were continuing with a group based in Tasmania for the lease of another floor of the building to store whisky and conduct whisky tastings.
