All Blacks fly-half Dan Carter suffered a broken leg in Saturday's Bledisloe Cup win over Australia and will be out of action for up to three months.
The New Zealand Rugby Union said Carter had broken a fibula in his left leg and picked up "significant" muscle and tissue damage in a 30-13 win at Sydney.
He will miss the All Blacks' remaining Tri-Nations matches and is in doubt for the tour to Britain at the end of 2005.
New Zealand begin that tour in October and play Wales on 5 November.
They will go on to play England, Scotland and Ireland.
Before that, the All Blacks face South Africa on 27 August with Aaron Mauger, Leon MacDonald or Luke McAlister being touted as possible replacements.
Meanwhile, Australia hooker Jeremy Paul has been ruled out of Saturday's Tri-Nations Test against South Africa in Perth.
Australia coach Eddie Jones said scans showed Paul had suffered nerve damage in his shoulder and neck against New Zealand, but he is hopeful of being fit for the return fixture in Auckland on 3 September.
Centre Stirling Mortlock will miss the rest of the Tri-Nations after damaging his calf, while fly-half Matt Giteau is doubtful for Saturday's game after suffering soft tissue damage in his lower back.
Australia A fly-half Lachlan MacKay was due to be called up as cover, but a knee injury ruled him out.
The Wallabies are already without number one fly-half Stephen Larkham for the rest of the campaign.