And Wales hooker Jonathan Humphreys also believes Ireland are the top team in this season's RBS 6 Nations Championship.

O'Driscoll and company will arrive at the Millennium Stadium next Saturday, seeking their fourth successive tournament victory after wins against Scotland, Italy and France.

They have not lost in Cardiff since 1983, and another triumph on Welsh soil would set Ireland up for a full-scale Grand Slam assault against England at Lansdowne Road eight days later.

Wales, meanwhile, are facing a championship whitewash for the first time in eight years following defeats at the hands of Italy, England and Scotland.

Both Humphreys, who is set to return from injury and reclaim the captaincy, and Wales coach Steve Hansen know that a tough afternoon at the office beckons.

"This is the best side that Ireland have had in as long as I can remember," said Humphreys, who is currently preparing for the game at a three-day squad training camp in Tenby.

"They've got a very happy bunch of players performing at the top of their potential, and it's going to be a massive challenge for us.

"Ireland have got a couple of world-class players. O'Driscoll is sensational - as good as you get - and it is a team that works hard for each other.

"I think it will be a bigger challenge than playing against England. In my opinion, Ireland are currently playing better than England, and they've also got the best player in world rugby (O'Driscoll) at the moment.

"They are the best team in the championship, and you would be bound to feel confident if you were in their position."