Bradman Best is set to start for the Kangaroos against Samoa in Sunday's World Cup semi-final.
His Knights contract runs to the end of 2027, and he can negotiate with rival clubs from November 1.
Parramatta are reportedly leading the chase and have made him a priority, while other clubs are also interested.
Best indicated talks with Newcastle could resume after Peter O'Sullivan's departure two weeks ago.
Speaking to News Corp, he rejected reports of a four-year Knights offer worth $1 million a season.
"I don't know where that offer came from. I don't know who leaked it, but it's not the case.
"I never received the deal which has been put out, and I don't know how that figure has been put out.
"At the moment, it's just all talk."
A deal is unlikely before the World Cup ends.
The Knights' cap is reportedly stretched by deals for Dylan Brown and Kalyn Ponga, but Best remains a retention priority for the 2026 grand finalists.