All Blacks midfielder Sonny Bill Williams will miss the first Bledisloe Cup test match against Australia following a World Rugby hearing overnight.

Williams was banned for four weeks following his red card against the British and Irish Lions, and it was initially thought that he would be able to serve his suspension before the first test.

Following his sending off, Williams subsequently missed the deciding Lions test and the Blues' defeat to the Sunwolves. The school of thought - shared by All Blacks coach Steve Hansen - was that he would be able to serve his suspension in preseason games for Counties Manukau, and possibly in a club rugby fixture.

"There's one game that's a bit contentious about whether they are going to consider it or not," Hansen told Radio Sport's Martin Devlin last week, referring to the club game.

"If that's not the case then we'll get him back just for the test match. If it's considered then we'll get him back for the game of three halves that we play every year before the Mitre 10 and Bledisloe starts," said Hansen.

However, in their statement, World Rugby said that "Following due consideration, the disciplinary committee has ruled that Williams' suspension will extend up to and including 19 August. As such, he is free to play again from 20 August."

The first Bledisloe test is on the 19th of August, in Sydney, meaning Hansen will likely turn to Ryan Crotty and Anton Lienert-Brown as his starting midfield combination for the clash.

At the judiciary hearing, the All Blacks claimed that Williams would play in pre-season for Counties Manukau against North Harbour, and in an inter-squad match involving a Counties B side.

While the Judicial Committee accepted that the game against North Harbour was meaningful, they were not satisfied that the inter-squad game on August 5 was set to "be a meaningful match" and would not "have had a meaningful playing consequence" for Williams, saying it was effectively "an internal club trial".

They then also rejected the All Blacks' "Game of three halves" against Counties and Taranaki, as it did not meet the World Rugby definition of a match, due to the introduction of a completely new team after halftime.

"When viewed objectively, it is, in our opinion, a training match, or, as was referred to by [Williams'] counsel, a warm-up match," argued World Rugby.

Williams has 48 hours to appeal the decision.