Tests do not come much bigger than Munster, and Cardiff Blues director of rugby Phil Davies admits his side are facing a huge challenge in their RaboDirect PRO12 clash on Saturday.

The Munstermen sit top of the table after seven games, of which they have won six, but Davies is also having to contend with a limited squad to choose from ahead of the Irish outfit’s visit to Cardiff Arms Park.

More than 20 players are unavailable either due to injury or international call-ups, and Davies has made five changes to the side that defeated Ospreys in the LV= Cup last week.

A new-look back row sees flankers Andries Pretorius and Josh Navidi declared fit to join forces with Number Eight Robin Copeland.

Prop Taufa'ao Filise is also recalled to the front row in the final change to the home pack while scrum-half Lewis Jones is named among the backs, partnering fly half Simon Humberstone on his first start for the region at the Arms Park, while Tom Williams will start at full-back.

Bradley Davies and Cory Allen joined the growing Blues injury list this week after picking up knocks with Wales and Davies admits it’s making his job tough.

"It's a challenging time of the year with players away on international duty and injuries biting. But you have to plan well and I enjoy this time of season,” he said.

"We are giving the squad a real test. We have over 20 players unavailable to us because of injuries and call-ups, but what that does is give other people opportunities.

"The players who have been given a chance recently have really stood up and done well and we are excited about what we are trying to develop.

"Munster have changed a lot over the last year or so, but they are top of the league at this stage so you have to give them huge respect for that.”

Cardiff Blues last four games in the RaboDirect PRO12 have all been won by the home side on the day, whilst their only victory over an Irish province in their last six fixtures was 21-10 at home to Connacht in September.

Munster have lost only one of their last six matches in all tournaments – 23-29 to Edinburgh at Murrayfield in the European Cup in October.

The Munstermen have won both of their clashes with Welsh regions so far this season and head coach Rob Penney has made five changes to the side that beat Ospreys in their last league outing at Thomond Park.

Dave Kilcoyne drops to the bench with James Cronin coming into the front rowwith the only other change in the forwards seeing Billy Holland return to the side.

There are three changes in the backs with Cathal Sheridan, JJ Hanrahanand Andrew Conway all coming back into the side.

And former Blues centre Casey Laulala admits it’s a must-win game against his old club.

“The boys want to play well to really establish themselves and the way we’re playing is not new to us so it’s just a matter of turning up mentally and playing well at the weekend,” he said.

“We must win the next two games in order to be on top of the Rabo and we’ll be trying to evolve our game again and that can give us a confidence boost.”

At Arms Park, 6.30pm.
Referee: David Wilkinson (IRFU, 24th competition game)
Assistant Referees: Greg Morgan, Justin Williams (both WRU)
Citing Commissioner: John Charles (WRU)
TMO: Paul Adams (WRU)

LIVE on S4C and RTE