But it is more likely that the Scarlets man will reach that landmark during the New Zealand global gathering in September.
And hitting 50 caps will prove correct the prediction of former Wales captain and Sale Sharks coach Kingsley Jones.
"I am surprised at how quickly the games come around and how quickly you tot up the caps," Rees told the South Wales Evening Post.
"I can remember training with Kingsley at Pontypridd and he turned and said to me one day that I had the potential to reach 50 caps.
"It meant a lot to hear that from such an experienced player as Kingsley and I hope I can prove him right and reach my 50.
"It's a great achievement and one I will look back on fondly after my career."
Rees is currently with the preliminary Wales squad in Spala, Poland, taking part in the first of two intense training camps.
And Rees, who featured eight times for the Lions in 2008, has been impressed by the emergence of young talents such as George North and Toby Faletau.
"It is great to have competition for places, it puts pressure on players and it means everyone knows that they cannot afford to turn in a poor performance," added Rees.
"Everyone must be at their best, not just during games but at training as well. Toby was awesome against the Barbarians and George has really taken his chance this year.
"We also have guys like Tavis Knoyle at scrum-half coming through. It's great to see, especially as we will need a strong squad to go to the World Cup."