The All Blacks and Wallabies will play a third Bledisloe Cup test match each year from 2012.
The New Zealand and Australian Rugby Unions say the additional and possibly deciding match will be hosted alternately by Australia and New Zealand.
This will add to the home and away matches the two teams will contest as part of the revamped Tri Nations tournament from 2012.
Australia will host the first extra Bledisloe Cup match in October 2012 after the expanded Tri Nations, which coincides with the planned introduction of Argentina into SANZAR's international competition.
New Zealand Rugby Union chief executive Steve Tew said fan research in Australia and New Zealand supported the Bledisloe Cup being contested over a three-match series.