The halfback is off contract at the end of next season and the Warriors have told Johnson he is free to explore offers from other clubs.
Canberra chief executive Don Furner said the club has not made any approaches to Johnson.
News Corp Australia reported earlier this month that the Raiders had been making discreet moves to bring Johnson to Canberra for next season.
"What happens is the manager rings you up and says would you like Shaun Johnson and 'do you think he would be a good player at your club?' and you don't say no," Furner said.