"Unfortunately, there is currently no concept that will secure jobs at the site in the long term," Gerd Walker, Audi's board member in charge of production, said.
An Audi spokesperson separately said that Audi had been talking to both carmakers as well as suppliers about a sale of the plant, declining to be more specific, but adding that bids could still be submitted.
Volkswagen in July cut its outlook after warning it may have to close Audi's factory in Brussels due to a sharp drop in demand for high-end electric vehicles, pointing to costs of up to 2.6 billion euros ($2.9 billion) to find an alternative use for the site or close it.
News about the difficulties to find a buyer for the factory come amid broader fears over possible site closures in Germany, considerations Europe's top carmaker first disclosed a month ago in what has developed into a major clash with labour unions.
Belgian newspaper De Tijd last month reported that Chinese EV maker Nio (9866.HK) was among the parties interested in Audi's Brussels site.
Asked about the report at the time, Nio's Chief Executive William Li denied that there were plans to acquire the plant.
Talks are now underway about a social plan for factory's staff, Audi said, adding a working group was also examining whether there is a future for the site within the Volkswagen Group.
($1 = 0.9028 euros)
