Newcastle United are keeping tabs on midfielder Siem de Jong and strikers Luuk de Jong and Ricky van Wolfswinkel, according to the players' agent.
Twente forward Luuk de Jong has recently been linked with a move to Liverpool whilst Sporting's Van Wolfswinkel has also been reported to be a long-term Manchester United target.
Siem de Jong, brother of Luuk, currently plies his trade at Ajax after coming through the club's famed youth academy.
The man who represents all three players, Louis Laros, says the trio are the subject of interest from the Tyneside club.
"There has been no contact in the last weeks," he told Record.
"I spoke with Newcastle about Luuk de Jong, his brother Siem and about Wolfswinkel, but all I know is that they have been checking on them.
"It is still soon to talk about a potential transfer."
Both Siem de Jong and Van Wolfswinkel have registered one cap for the Netherlands whilst Luuk de Jong recently gained his sixth cap and has one international goal.