The six-level commercial office building at 83-85 Market Street had attracted the attention of potential buyers from Sydney and interstate, since it was put on the market in March.

MMJ Real Estate Wollongong's Travis Machan said the Sydney-based buyer saw genuine "value add" potential and planned an immediate upgrade and filling the current rental vacancies.

The Market Street property, with a net lettable area of 1843 square metres, is partially leased to tenants, including Kells Lawyers.

It has secure undercover parking beneath, and a sealed site at 92 Market Street provides an additional 21 car spaces.

Mr Machan said the sale was another example of the nationwide interest in Wollongong as an investment hot spot.

He said there were a number of potential buyers in the race.

"This was a very pleasing result from a successful marketing campaign with a notable interest from Sydney and interstate," he said. Although this was expected, we were pleased with how many parties formally expressed interest.

"The property sold for $4.3 million with numerous competing offers in close pursuit.

"The building is well located in the CBD and will continue to remain a convenient leasing opportunity for savvy office tenants."