De Bruyne signed for Wolfsburg at the beginning of 2014, having failed to force his way into the first team at Chelsea.
The Belgium international has impressed since arriving in the Bundesliga on a permanent basis, and is said to be attracting attention from the likes of German champions Bayern Munich.
"I never said there had been contact with Bayern," De Koster told Sport1. "There's been no contact with Bayern at all and no contact with any other club either.
"Kevin has played a great season so far with Wolfsburg and it's only normal that other clubs are watching him, but nobody has spoken to me.
"I have great respect for Wolfsburg and I thank [sporting director] Klaus Allofs for giving Kevin the chance when he was not in a good situation with Chelsea and could not play.
"We can only thank Wolfsburg. He signed a new contract until 2019 with them in January and, after a good World Cup, he's been in good form for Wolfsburg.
"Naturally he is only thinking about Wolfsburg. Kevin only wants to stay here."
