The Sun says Toon have slapped a £15million price tag on in-form keeper Krul.
The Magpies want to scare off Tottenham and Chelsea this month.
Both want the impressive Holland stopper, 23, but Newcastle insist only a huge offer will get 6ft 4in Krul.
A Toon source said: "Tim is now widely recognised as one of the best goalkeepers in the Premier League.
"It's a very specialised market when you are searching for a keeper of that quality.
"You've got to be talking £15m, maybe more. That's how highly we value him."