Warren Gatland© Stu Forster/Getty Images

Wales head coach Warren Gatland admits that he has some "tough calls" ahead as he applies the finishing touches to his 31-man World Cup squad.

Gatland's squad will be announced at the Millennium Stadium on Monday, and he acknowledges that "24 or 25 players" have already booked their places. But the New Zealander also needs to make decisions on players like wing Liam Williams and fly-half Gareth Anscombe, who are both currently sidelined through injury, although prop Samson Lee appears firmly on course to make the final group following five months out because of Achilles tendon trouble.

"Samson is making brilliant progress," said Gatland, whose team continued World Cup preparations with an impressive 16-10 victory over RBS 6 Nations champions Ireland in Dublin on Saturday. "He has been involved in live scrummaging, and he is running. We just need to get him fit, and hopefully he doesn't break down."

Williams is recovering from a foot injury, while Anscombe recently suffered an ankle problem during training, and Gatland must decide whether or not he can potentially go into the tournament with any players who might be unavailable for the opening Pool A flurries.

"Liam Williams is ahead of where we expected him to be, but he's still probably not going to be involved for the first game or two, or the first game anyway," Gatland added. "The medical team are seeing where Gareth Anscombe is at, and that is a two or three-week injury as well. We are going to have to make a couple of tough calls on players.

"You might be able to carry one or two, but you've got to be careful how many injured players you go into the World Cup with. The last World Cup, we had a couple, and we may end up being the same this time. We have discussed as a coaching team what we think, and we have probably got 24 or 25 players nailed down."

If Williams and Anscombe are ruled out of the selection equation, then it could open the door for 23-year-old Bristol back Matthew Morgan in a squad that looks set to comprise 14 backs and 17 forwards, although Morgan's impressive game-breaking prowess could make him an automatic choice. Exeter prop Tomas Francis, who enjoyed a strong Test debut against Ireland, and Gloucester flanker Ross Moriarty both look set to make the final cut, with Gatland needing to lose seven more players from a training group that was reduced earlier this month when casualties included British and Irish Lions trio Richard Hibbard, Mike Phillips and James Hook.

Francis took his opportunity at the Aviva Stadium during a strong Wales scrummaging performance in the first-half, and Gatland said: "He has made amazing progress with us in the last six months.

"He is only 23. For him, there is no pressure, it's just about learning, and I think he will continue to get better."

One player guaranteed his place at the World Cup is juggernaut wing George North, who played the whole 80 minutes of his comeback match after five months out. He suffered three concussion injuries last season, and North's return to action also saw him become the youngest player in rugby union history at 23 years and 138 days to win 50 caps for his country.

"We were confident that he was going to be right," Gatland added. "I thought he did a good job going into the centre for us as well when we took Jamie [Roberts] off. There has got to be some recognition for George on becoming the youngest player in world rugby to win 50 caps. It is an incredible milestone for a 23-year-old to have done that."