As yet there has been no reason given for Williams staying mum during the anthem, with social media users left to speculate.
Halfback TJ Perenara wore a "Ihumātao" wrist band in support of the protestors at an Auckland housing development site during Bledisloe Two.
The Ihumātao protest is an occupation of the land near the protected Ōtuataua Stonefields in Māngere, in opposition to the housing development planned by Fletcher Building.
Coach Steve Hansen brushed off Perenara's decision after the test saying: "It's his decision, it doesn't bother me. I didn't even notice it, to be honest. They write all sorts of stuff on their wrist bands these blokes today. I don't know what I'd write on mine if I had one."
One social media post asked if Williams, who has Samoan heritage, was also supporting the Ihumātao protestors.
Three years ago, New Zealand Māori prop Kane Hames wore a "Standing Rock" wristband in support of the indigenous people in North Dakota, USA.
Then, New Zealand Rugby, which has set guidelines around what players can and cannot write on their apparel during matches, stopped short of telling him not to do it again.
At the time, then NZR general manager Neil Sorensen said: "There's an expectation that staff and players do not involve themselves in conduct that may bring their employer, and the game, into disrepute."
