Alan Pardew says clubs will have to "blow the doors off" to stand any chance of landing Newcastle's big-name players.
Stars such as Tim Krul, Cheick Tiote, Yohan Cabaye and Hatem Ben Arfa have all been linked with moves away from St James' Park.
However, with the Magpies in a healthy financial position, Pardew has warned that it will take a breathtaking offer to persuade owner Mike Ashley to cash in.
"I feel we are in a strong position financially to hold on to our players," said the Newcastle manager. "If one of our top players goes, it will be a bid that blows the doors off. That's it."
Newcastle are yet to strengthen the squad which finished a disappointing 12th in the Premier League last season, while Steve Harper, Danny Simpson and James Perch have all left the club.
Pardew is keen to recruit a proven striker with Aston Villa's Darren Bent, with whom he worked briefly at Charlton, among his targets.
He said: "We are strong in some areas and weak in others. I think it would be nice to strengthen in some areas.
"The obvious target is a striker and we have four or five targets.
"It is difficult, because I know there is speculation, particularly about Darren Bent."