Ryan Jones (AFP)

Experienced flanker Martyn Williams takes over the captaincy while Ospreys No 8 Ryan Jones is replaced by Gloucester captain Gareth Delve in one of three changes to the side beaten 26-20 by tournament leaders France last time out.

Delve is now set to win a first Wales cap since the 2008 South Africa tour, with Williams leading out his country for the seventh time.

British and Irish Lions hooker Matthew Rees makes his first Six Nations start this season after recovering from a groin injury, replacing Huw Benett, while lock Luke Charteris comes in for the injured Deiniol Jones.

On the bench Dwayne Peel provides scrum-half cover for Richie Rees after a knock suffered on club duty by Mike Phillips ruled the Ospreys No 9 out of contention for the trip to Croke Park.

"Ryan has been managing his calf, but it has hampered his involvement in training," said Wales coach Warren Gatland after announcing his side on Tuesday.

"He needs to get it right for his own sake, as well as for his region, who have some big matches of their own coming up, and for the sake of the national cause as we count down to the (2011) World Cup," the New Zealander added.

"But it is an opportunity for Martyn, who is one of our key leaders, to captain Wales again and rise to that challenge.

"This is a great opportunity for Gareth Delve, who we have been keeping a close eye on and who is also a leader himself.

"We feel we have a loose forward trio here who will be competitive."

Wales have won just one of their three matches in this season's Six Nations and face an Ireland side that, although unable to win back to back Grand Slams, remain very much in the title hunt after a 20-16 victory away to England at Twickenham in the third round.

"Ireland are an impressive and experienced side with a pack of players who have been around for a long time and who are tough players," said former Ireland coach Gatland.

"We know we need to improve, but we do think we have the talent and ability in this squad to match any squad and are confident we are good enough to win this match if we can get things right on the day."

Wales (15-1):

Lee Byrne; Leigh Halfpenny, James Hook, Jamie Roberts, Shane Williams; Stephen Jones, Richie Rees; Gareth Delve, Martyn Williams (capt), Jonathan Thomas; Luke Charteris, Bradley Davies; Adam Jones, Matthew Rees, Paul James

Replacements: Huw Bennett, Rhys Gill, Ian Gough, Sam Warburton, Dwayne Peel, Andrew Bishop, Tom Shanklin