Cardiff Blues flanker Williams, last season's Six Nations player of the tournament, will spend most of the week with his family.
"There is no timing on it, but I don't envisage seeing Martyn much this week," said Wales' team manager Alan Phillips, after the squad assembled at their Vale of Glamorgan training base.
"I spoke to him, and it is safest to presume he is not available. It wouldn't be fair to the boy, and all our thoughts are with him."
Wales coach Mike Ruddock, meanwhile, has called up Llanelli Scarlets flanker Dafydd Jones into the squad.
Jones scored the winning try in Llanelli's dramatic European Cup victory over Edinburgh two days ago, and is slowly recapturing the form that he displayed at times last season.
"We need a bit of extra cover at six, and Dafydd is a good man to have around," added Phillips.
Wales, who have not beaten the All Blacks since 1953, were taking stock of their injury situation.
Lions Gavin Henson, Tom Shanklin, Gethin Jenkins and Ryan Jones have already been ruled out of the All Blacks encounter through injury, together with Newport Gwent Dragons back Hal Luscombe.
Llanelli and Lions scrum-half Dwayne Peel is a major doubt because of an ankle problem that kept him out of his region's opening two European Cup games, but fly-half Stephen Jones proved his fitness after injury when he played a full part in Clermont Auvergne's victory over the Ospreys in France.
Ruddock is due to name his team on Tuesday, a line-up that is likely to include Newcastle captain Colin Charvis after he missed last season's Grand Slam campaign through injury, while Worcester prop Chris Horsman could also feature in the match day 22.
Horsman, who recently qualified to represent Wales on residency grounds, is currently suspended after being cited for stamping during a Guinness Premiership game earlier this month.
But the ban expires on Friday, making him available for Saturday's Millennium Stadium showdown.