It was unlikely consent would have been given if the owner did apply, he said.
"I probably wouldn't encourage them to apply. The most expedient route would be to remove it, I would think."
The brand logos were different from signs on other flats, which had been named by tenants.
"Obviously, there is a whole swag of those, which is part of the character of that environment."
Radio Network promotions co-ordinator Laura Campbell said it arranged with the landowner for the sign to be put up and was not aware a resource consent was needed.
"Basically, the owner of the flat gave us consent, that's why we pushed forward," she said.
Flat tenant Abby Van de Vlierd, 20, said the sign was "harmless" and the council asking for it to be removed was "pathetic".
The tenants had been given movie tickets and pizza vouchers as part of the sponsorship arrangement and Ms Van de Vlierd was disappointed the flow of free products could stop.
Otago Real Estate, which is listed as the contact address for the owner, did not return calls yesterday.
Former Otago student and member of staff, Sarah Gallagher, who is writing a book on the history on named student flats in Dunedin, said sponsored student flats was a relatively new phenomenon.
However, the first named flat she was aware of - a flat in Leith St called "The Batch" - dated back to the 1930s. The practice became relatively common by the 1960s, she said.
Otago Business School senior marketing lecturer Dr John Guthrie said sponsoring a student flat was a "mildly risky strategy" - especially if the misbehaviour seen in the early 2000s returned.
"If it was in the wrong flat and the wrong place and the wrong students in it, that could backfire quite badly," he said.