The midfielder is hoping to leave Ajax this summer.
He was quoted in the Dutch Press earlier this month as saying there had been “contact” with Newcastle United.
However, it is understood no move is imminent for De Jong – brother of former Newcastle loanee Luuk – although he does interest the Magpies.
The 25-year-old has 12 months left on his Ajax contract, and he has an agreement with the Dutch champions that he will be allowed to leave this summer.