The Anderlecht midfielder has emerged as a target for the Hammers this month as David Moyes searches for reinforcements.
West Ham assistant manager Stuart Pierce reportedly travelled to Genk last weekend to watch Dendoncker.
However, any potential deal is unlikely to be concluded before the final week of the January transfer window.
Anderlecht are believed to have set an asking price of €20m for Dendoncker, but will not sell if they fail to identify an adequate replacement in time.
The 22-year-old, who is reportedly keen on a switch to the Premier League, has made 155 appearances and scored ten goals for Anderlecht. He has been capped four times for the Belgian national team since his debut in 2015.
"I don’t think so. I don’t think we will," he said.