The club will sell the Dutchman if the right offer is made.
The Magpies are expected to be busy in the summer transfer window as they look build a squad capable of securing a return to the Premier League.
They have already brought in three new faces, with Matz Sels, Matt Ritchie and Dwight Gayle all arriving at the club.
Wednesday afternoon saw them linked with Atletico Madrid defender Jesus Gamez by Spanish publication AS.
Manager Rafa Benitez keen to improve his struggling defence and the Spaniard is likely to be one of several defensive recruits added.
And according to the Chronicle his impending arrival means that Newcastle will listen to offers for Janmaat should the price be right.
The full-back is one of several first-team stars, alongside the likes of Moussa Sissoko and Georginio Wijnaldum, to have been linked with an exit following Newcastle's relegation last season.
So far the Magpies have been resistant to any sales where possible but with potential additions their stance on Janmaat will allegedly change.
It now remains to be seen if any clubs will make an acceptable offer, with CalcioMercato reporting that Inter Milan and Juventus were keen on the Dutchman.