But his manager, Chris Orr, said Williams was in no hurry to sign.
"The Bulldogs have contacted us about an extension," Orr said. "We haven't gone into the terms but I'd assume they'd like to sign him for as long as they possibly could.
"We don't want Sonny to get too far ahead of himself. As a manager, I wouldn't sign a player to a deal two or three years down the track."
Williams might be too expensive for the Warriors, but the
reported they could free up money for him following last week's ditching of Sione Faumuina and with captain Steve Price off-contract at the end of next season.
Sonny Bill in action for the Bulldogs
"Being a Kiwi boy, and an Auckland boy and a great player, we'd certainly be interested in Sonny Bill Williams," Warriors chief executive Wayne Scurrah told the newspaper.
English clubs are also bound to be keen on Williams, who last year knocked back a huge offer, reported to be $A900,000 ($1.06 million) a season, from St Helens.