Rob Howley’s men enter the Championship on the back of seven consecutive defeats.
But Rees is confident Wales can rediscover the form that saw them sweep aside all opponents in last season’s tournament.
“That (being written off) was always going to be the case with the autumn series we had and losing our last seven,” said Rees.
“But we put enough pressure on ourselves as a team and we know how important it is to get off to a good start in this competition against a very good Irish side.
“We believe we’re good enough to win the Grand Slam again and it starts on Saturday.
“We won it last year and we know from previous championships how important it is to get a good start in this competition.”
Wales can however take confidence from the fact that they have triumphed in their last three encounters with Ireland.
Last season’s victory at the Aviva Stadium, which got the Grand Slam ball rolling saw Wales at their devastating best with George North and Jon Davies running riot.
And Rees reckons Wales’ backs can roar again providing they are given a solid forward platform.
“It’s important as a pack that we dominate up front to give possession to our backline. That’s the challenge as a forward eight.
“We need to use that (2012) again. I’m pretty sure Ireland will remember how dangerous they are.
“We have some talented backs and we have to give them a platform because we know how dangerous they can be with ball in hand.”
The 32-year-old faces a challenge from Richard Hibbard and Ken Owens to start at hooker for Wales.
But if selected he is relishing his personal battle with Ireland’s Rory Best as the duo bid to put a marker down ahead of the Lions tour to Australia this summer.
“There’s no better stage than the Six Nations,” said Rees.
“In terms of fitness and injury I’m fine. I haven’t played that much rugby since the autumn.
“But the Lions is always at the back of your mind and it’s important I start putting in the performances to get me there.
“Hopefully that will start this weekend.
“The first thing is to start against Ireland then to put a performance in that is worthy of a Lions call.
“I just want to make sure my form is up there against Ireland and keep it at a high level for the rest of the campaign.
“Rory is one of the best hookers in European rugby over the last year and it would be great to face him.
“His all round game is pretty good, but I’m looking forward to the challenge if I start.”
