Bradman Best says a reported contract offer worth about $1 million a season over four years was never made.
"That hasn't been the case," Best told News Corp. "I don't know where that offer came from. I don't know who leaked it, but it's not the case."
The Kangaroos centre is off contract at the end of 2027 and can speak to rival clubs.
Before Australia's group match against Fiji, Best said he hoped Newcastle would offer improved terms, adding that his heart was with the Knights.
He had starred in the club's finals campaign and directed his frustration at former recruitment boss Peter O'Sullivan, now with the Broncos.
Best said he understood O'Sullivan was acting in the club's interests and that his manager was acting for him.
"But there's a way to go about things. In some way, shape or form, we felt a bit disrespected with how he went about things," Best said.
He said calls went unanswered and attempts to arrange a meeting failed, though he acknowledged the situation "probably went both ways".
Best made the comments ahead of Sunday's semi-final against Samoa.