Former skipper Ryan Jones and winger Morgan Stoddart are also sweating over their fitness after they took part in ‘limited training’ with the rest of the squad.

Hooker Rees has had a hamstring problem since the 24-16 win over Italy with Hook, who has already played at full-back and fly-half in this year’s tournament, struggling with a calf.

Jones has also been plagued by a calf and Stoddart his shoulder and with back-up hooker Richard Hibbard also not fully fit after picking up a knock with the Ospreys Huw Bennett has been called in as cover.

“Both Matthew [Rees] and Morgan [Stoddart] have responded well to extensive treatment since picking up their injuries against Italy,” said Wales national performance medical manager Prav Mathema.

“Matthew has a slight hamstring problem and Morgan sustained an injury to his shoulder during that match, but the medical staff has managed both players very well and together with the hard work they have put in so far we expect both to be available for Ireland .

“Richard [Hibbard] has a shoulder problem sustained during his outing for the Ospreys this weekend and he needs rest at the moment, although he too should be okay for Saturday.

“The issues with Ryan [Jones] and James [Hook] just mean they have taken a limited part in some sessions so far during our preparation but, again, both will be fine.”