But he insists the forwards that led Wales to a third Grand Slam in eight years are the best yet.
Rees, who has been sidelined with an ankle injury, is set to jet Down Under for the three-Test tour of Australia in June, and he has urged Wales to dominate the forward battle.
"This is definitely the best Welsh pack I've been involved in," said Rees.
"You've just got to look throughout the forwards, with the players we've got on the bench as well.
"We've got so much strength in depth in this squad, it's great for Welsh rugby and great for the players involved.
"It must be hard for the coaches to actually pick a starting eight. That competition is something we've lacked over the years but now anyone can fill in."
There has been a perception in recent years that the pack is the Wallabies weakness. And while Rees reckons they have improved he still believes Wales can dominate up front to release the Dragons' red-hot backs.
"It's definitely an area we need to go after. There has been a big question mark over their forwards over the last couple of years.
"If we can take them on up front, then we know what a world class back line we have and I'm pretty sure if we can provide our backs with ball, we can cause some damage.
"We all know the game of rugby starts up front, so it's about making sure we get the upper hand there."
There had been some doubts over Rees' involvement in the tour, following the ankle injury he suffered against Munster.
But he has declared himself fully fit and is relishing the trip Down Under, having missed last year's World Cup.
"I hurt my ankle against Munster just over a month ago and I've been out for longer than first thought," added Rees.
"But I started back running this week and everything has gone to plan, so I'm just looking forward to getting back into the rugby side of it now.
"It was very frustrating to miss out on the World Cup. But playing a part in the last couple of games in the Six Nations and winning a Grand Slam again was great.
"For some of the boys, it's been a tough old season, but we've got to look forward to going down to Australia and putting in a big fight.
"The good thing about the squad at the moment is we've got plenty of momentum after the World Cup and the Six Nations and everyone is looking forward to the challenge Down Under.
"We know we've got to be on top of our game to beat the Aussies. For us, it's a case of making sure we cut out the errors in our game. Against the best teams in the world, they are going to capitalise on those mistakes.
"It's making sure we do the basics well. We've got the players in the team who can finish things off and everyone is looking forward to the tour."