Liam Williams must play 15 for Wales - Davies and Williams

Liam Williams was part of the Wales team which beat South Africa 12-6 in November

Former Wales players Jonathan Davies and Martyn Williams say Liam Williams should play full-back for Wales in the Six Nations ahead of Leigh Halfpenny.

Williams, 23, who has won 18 Wales caps, injured his shoulder in Scarlets' 22-7 defeat by Glasgow on Friday.

Wales coach Warren Gatland has typically favoured Halfpenny at full-back, but Davies says he would pick Williams if he recovers from injury.

"He's playing at the top of his game," said the former fly-half, 52.

"Confidence is oozing from him, he just glides past people, he looks comfortable with the ball and he's brave under the high ball.

"He has got to start at 15 [but] that is a concern, the shoulder injury . . . Hopefully he's going to be fit."

The Morriston-born player started on the wing in Wales' historic victory against South Africa in November, though he did play at full-back in the victory over Fiji when Halfpenny was rested because of concussion sustained in the previous Test against Australia.

Williams produced a man-of-the-match performance against Fiji from full-back and former Cardiff Blues flanker Martyn Williams says he "brings something different to our backline."

The 39-year-old continued: "We've got fantastic powerful athletes, but he's just a natural footballer. I think he's a brilliant player.

Leigh Halfpenny (C) congratulates Liam Williams (R) after Wales beat South Africa, while Alex Cuthbert (L) looks on

"Then it's a straight shoot out who you pick on the wing, whether it's Halfpenny, George North or [Alex] Cuthbert...three into two.

"Are you going to leave George North out? I just can't see that myself.

"The next two or three weeks are going to be key on who is in form."

Wales begin their Six Nations campaign at home to England on Friday, 6 February, before ending the tournament away to Italy on Saturday, 21 March.

Davies, who won 32 caps, believes Gatland's selection may depend on who is given responsibility for kicking Wales' goals.

"It all depends on whether you give Dan Biggar the kicking duties," said the former Neath, Llanelli and Cardiff player.

"If you do and you are confident in his kicking then unfortunately Halfpenny might miss out.

"But then again if Leigh Halfpenny is the kicker then it's Cuthbert who loses. It's as simple as that.

"You need strength in depth to make the tough choices."