Gear is not thought to be looking offshore but needs to decide whether to stay with the Hurricanes or shift south to play for the Highlanders.
Other players to sign beyond 2011 recently include Owen Franks, Richard Kahui, Andy Ellis, Isaia Toeava and Piri Weepu.
Tidying up the last few players' paperwork will be a major relief to the All Blacks.
The situation wasn't so clean at the 2007 World Cup, when several players were distracted by ongoing negotiations during the tournament.
Quite incredibly, McCaw signed his contract extension the day before the quarter-final loss to France.
"I think it is really important for these guys to have clear minds at the World Cup," says NZRU general manager of professional rugby Neil Sorensen. "It is one less phone call they have to take from their agent and worry about."
Williams is the biggest capture for the NZRU, as it has always been uncertain whether he would stay beyond this year. He signed a one-year deal in 2010 so he could review his options.
He's made the same deal again, which means the NZRU will have to engage in yet more lengthy negotiations almost as soon as Williams reports back for Super Rugby duty.
Williams said last week that he was reluctant to announce his plans ahead of the test, as he feared it would overshadow what was a critical game for him and many of his teammates.