The 2005 Lions tourist has not played for his country since facing England in a World Cup warm-up match last year.
But Rhys Priestland's six-month injury absence has opened the door for Henson to make a return to the international stage.
Dan Biggar and James Hook are the front-runners to fill the void at 10 in the upcoming Championship but London Welsh head coach Lyn Jones reckons Henson can play his way into contention by starring for the Exiles in the festive season.
"Gavin is these days a more confident individual than I have seen from him before and I'm sure things will continue to go well for him on the rugby field," said Jones in the Western Mail.
"Things were on course for Gavin as regards catching the eyes of Warren Gatland and Six Nations selection, but his lack of game-time over the past few weeks could count against him.
"Can he come back and challenge James and Dan for the Wales No. 10 jersey against Ireland? I would say yes, he can.
"Everybody knows how much talent Gavin possesses. He's certainly worth a look at by the Welsh selectors.
"Provided he is fit, it's going to be a big sequence of games for us and Gavin. He has got a lot of work to do between today and the end of January to impress the Welsh selectors.
"It's up to them to determine whether his form is good enough for the Six Nations, but he knows how to control a game, has vision, skill and a prodigious boot.
"He's been excellent for us, a class act. What he has done is embrace his best position, which is No. 10.
"He played some fantastic rugby at outside-half when we were at the Ospreys, controlling matters when we won our first Celtic League title during the 2004-05 season."
Henson is currently sidelined with a calf injury, having overcome the back problem that has kept him on the sidelines in recent weeks.
He will miss Sunday's Amlin Challenge Cup clash with Grenoble but is set to return to action against Worcester Warriors next Friday.
"His last match was against Bath on November 4," added Jones.
"We won and Gavin did really well, but he had to come off because of the back injury.
"He was cleared to come back from that a couple of weeks ago, but picked up a calf injury in training. We did not want to rush him back from that and risk a recurrence.
"Gavin has had calf problems in the past so we have had to be careful. He will miss our Amlin Challenge Cup encounter with Grenoble in Oxford on Sunday, but we're expecting him to be available for our league game at Worcester next week."