Brisbane chief executive Bruno Cullen questioned the legitimacy of huge Japanese rugby union offers targeting NRL stars after Queensland Origin forward Sam Thaiday re-signed with the Broncos for two more years on Friday.

The Broncos are currently negotiating to re-sign Origin and Test fullback Karmichael Hunt, linked to an unconfirmed $1 million-a-season offer from Japanese rugby interests.

Cronulla and former Broncos back Fraser Anderson is the only NRL player so far caught by Japanese interests, reportedly agreeing to a two-year, $400,000-a-season deal with Kobe Steel.

However it has been reported high-profile club Suntory's main target is Hunt on the advice of former Wallabies coach Eddie Jones.

Describing 23-year-old Thaiday's signature as a "vital signing", Cullen - battling to retain Hunt and captain Darren Lockyer - questioned the credence given to Japanese offers when players are negotiating deals.

"It's certainly grabbed the headlines over the last week or so," said Cullen on Friday.

"I think it's coming from the player managers.

"I don't think there would be people in Japanese rugby union who would know a lot about Australian rugby league players or how they would assimilate to Japanese rugby union.

"Someone in Australian has to be driving it and I'd say it is the player managers.

"They're not rugby league player managers, they're player managers for whatever they can get for a player, whether it be a deal with a soccer team, a rugby union team, a rugby league team or a commercial.

"That's their job and you've got to respect that."

Cullen is yet to see any proof of the reported offers.

"I've yet to see, other than Fraser Anderson, the numbers, and we're not even sure of those yet," he said.

"This million dollar talk with Benji (Marshall) and Karmichael, nobody has seen anything on paper and that includes the managers.

"If you ask to have a look at what the offers really are, there's none there.

"Are we a little concerned about it?

"Yes, I think we are.

"If that sort of money is really there, and I don't know enough about Japanese rugby yet, but you've got people like Eddie Jones who've focused on Karmichael because they think he'd be a sensation up there.

"We'd have to be concerned because we could get into a bidding war with those sorts of figures."

Thaiday, who has played 81 games for Brisbane, six Origin and two Tests, was sounded out by rival clubs but never had any intentions of leaving.

"I did have a sticky beak but in the back of my mind the Broncos was always where my heart was," Thaiday said.

"Brisbane was always my first choice.

Cullen said he was "relaxed" at where negotiations were with Hunt and Lockyer.

"We're at the negotiating stage and I'll be having talks with both their managers next week," he said.

Brought to you by AAP © 2024 AAP