The Toulon star quit Australia with a "bitter" taste in his mouth two years ago.
But the lure of the 2015 World Cup could prove decisive although Giteau admits it would be a massive challenge.
''I'd love to be involved and given an opportunity but I just don't know how realistic that is,'' said the 30-year-old.
''I'm enjoying my rugby here. You'd never knock back the chance to play for your country but I think being over here now and not being in Super Rugby, you have those doubts about whether you still are good enough to play top level rugby like that. There are a few questions to answer first.''
Giteau left Australia under a cloud after being left out of Robbie Deans' 2011 World Cup squad despite being ever-present in the prior months.
He admits the omission was difficult to take initially but he looks back on his international career with pride.
''Not getting the opportunity is OK, I've been fortunate enough to have so many coaches show a lot of faith in me and continue to pick me even if my form didn't warrant it,'' said Giteau.
''I have no problems if a coach doesn't feel you're best suited for the group, but certainly the way I was told [about the World Cup omission] and the way things just ended left a bitter taste for me.
"That was my initial reaction but I feel and have nothing but fond memories of my time in Australia, and that I had the opportunity to play for Australia so many times, I'm very thankful for that.''
Deans departed the Australia position following the Wallabies 2-1 series defeat to the British & Irish Lions.
Ewen McKenzie has been installed in his successor and already admitted he will take a 'never say never' stance on players.
Giteau reckons his appointment was the right decision and although it could open the door for him to make an international return he remains a realist
''With the Reds, Ewen seems to know his players, he seems to know how to motivate players and keep them interested, focused and quite disciplined as well, and that will be a big thing for the group," added Giteau.
''Time will tell whether he was the right appointment but certainly change needed to be made, and I think at this point in time Ewen was probably the best man for the job.
"Robbie had had his opportunities at trying to build success and get the team going in a certain direction, so I feel it was time for a change.
"I have at least this season to go [on my contract] and I might possibly reassess after that but like I said at the moment, they're all big ifs.
"I've got a two-year deal here, I'm enjoying my time here, my family's happy, I'm happy and I get the opportunity to play with so many great players, so I'm quite fortunate in that regard.
"For me, now that some time has passed, it's been the best thing, I would have loved to have been involved in the  World Cup, I'm not saying that I wouldn't have been.
"I would have done anything to have been involved in the squad, helping out however I could. But it has been a nice change … When you watch things like the [British and Irish] Lions Tests you would still love to be a part of the big games, but now that I've had a bit of success here I can let that go and wish the guys there all the best."