Hook (shoulder) and Lydiate (ankle) both went off during Wales' punishing Pool D victory over Samoa in Hamilton 16 days ago and have not played since, while Williams missed runaway victories over Namibia and Fiji due to a thigh strain.

But they will take part in training tomorrow, giving Wales coach Warren Gatland a full squad of 30 from which to select his starting line-up.

Lydiate's recovery has proved particularly impressive after he departed with ankle ligament damage just 10 minutes into the Samoa game.

As part of his initial bid to regain fitness, he woke at two-hourly intervals throughout the night to ice his ankle, and that approach now looks as though it has paid off.

Former Wales captain Ryan Jones took over from him in the Namibia and Fiji fixtures, while Leigh Halfpenny and then Lee Byrne deputised for Hook, with Halfpenny moving from full-back to wing against Namibia and Fiji.

"Dan, James and Shane have all been passed fit to train tomorrow," said Prav Mathema, the Welsh Rugby Union's national medical performance manager.

"Pending any adverse reaction, we expect them all to be available for selection against Ireland this weekend.

"Gethin Jenkins and Sam Warburton are also both fit for selection following calf cramp experienced during the end of the Fiji fixture."