Gallen, who will fight the New Zealand superstar's close friend and former rugby union teammate Liam Messam in next month's Fight For Life charity event, opened up about his boxing ambitions as the Kangaroos prepared for Saturday's World Cup final at Old Trafford.

At the age of 32, Gallen is beginning to consider life after football and he admits the ASADA scandal that has hung over the Cronulla captain and everyone else at the club since February was constantly in the back of his mind.

However, Gallen intends to serve out the remaining two years of his contract with the Sharks and he is not sure how serious an option boxing really is.

"I will put it out there right now," Gallen said when asked about fighting Williams, who holds the New Zealand heavyweight title and earlier this year won a points decision over former world champion Francois Botha in just his sixth professional bout.

"Maybe one day down the track, if I got good enough, I would be interested in fighting Sonny, but certainly I am not at that level yet," he said.

"People talk about Sonny and whether he can fight or not, and I think he can. I have been to training and watched him spar and I think he goes pretty good.

"Sonny beat Francois Botha, and I know he was 44 years old and past his best, but experience counts for a fair bit and he has fought all the best boxers in the world. If I was to fight Sonny I don't think I would be any competition for him right now."

However, Gallen hopes to get an indication of whether he has a future as a boxer when he fights Messam in Auckland on February 14.

Having arrived home from the World Cup just nine days earlier, Gallen will have little time to prepare for the fight. His plans to do some sparring in England while on tour with the Australian team for the World Cup failed to come to fruition.

"I haven't had the opportunity to spar anyone over here and by the time I get home I am not sure how much sparring I will get in or how effective it will be," he said.

"At the end of the day, I can punch pads and punch punching bags all I like, you have got to get in there and spar for boxing. You can punch a bag for three hours and it is not going to make a difference.

"But I want to do it so I am not going to pull out. I am nervous but I am excited about it and we will see where that goes. I think it might give me a bit of an indication of where I have to get to."

The charity fight should at least give Gallen something else to focus on as he and the rest of the league world wait for ASADA to hand down their report into allegations that banned substances were included in the supplements program at Cronulla in 2011.

With the Sharks being the club most in the spotlight, and Gallen being not just their captain but the highest profile of the 31 NRL players interviewed by ASADA, he has become the face of the scandal.

"We will all be back into the grind of it when we get home," Gallen said, referring to the media as well as the Cronulla players.

"But what can you do? Hopefully we get to go back home and enjoy Christmas and then get into pre-season training mid-to-late January.

"The players have completed what we have had to do and I don't know what the next process is, I really don't. There has been a lot of uncertainty since day one to be honest.

"What a shock it was. It just seemed to come from nowhere and then you guys were outside our houses and at training but, as I said, we don't know what is going on, you don't know what is going on and we have just got to deal with it as it comes.

"That was before the season started and we are still here, we are still playing footy and we are in the World Cup final."

At times during the season Gallen had clearly been consumed by the issue, but at the Kangaroos hotel in Manchester this week, he appeared relaxed and remarkably refreshed considering he and Cameron Smith are the only Australian players not to have been rested during the World Cup.

"It has been a lot easier being here, but you never forget about it," he said of the ASADA investigation.

"It is always in the back of your mind – just hanging there somehow – but it has been really enjoyable being over here and being with all these boys and just getting away from it."

While he only intends to play another two seasons in the NRL, Gallen would not consider retiring from representative football before then and he wants to win a World Cup and finally lead NSW to an Origin series victory.

"There was a little bit of talk this year about me and rep footy and I don't want to give myself a rap but I just think when I play rep footy I play well," the Blues captain said.

"I think I am going to play rep footy until there is someone better to take my spot and that will be the selectors' decision, but I am not thinking about giving it up.

"I will play the next two years of my contract and I think that will do me, to be honest with you."

Perhaps then he will consider himself ready to fight Williams.