SYDNEY John O'Neill will step down as Australia Rugby Union (ARU) chief executive at the end of the month, the organisation said on Friday.
Deputy Chief Executive Matt Carroll will take over on an interim basis from November 1 while the ARU looks for a replacement.
O'Neill was expected to step down in 2013 when his contract ended but had chosen to bring that forward to concentrate on his other business interests, the ARU said in a statement.
"John's resignation enables the board to put in place new leadership to build on that platform and to drive our substantial agenda over the next five years, while enabling John to focus on his broader business interests," ARU Chairman Michael Hawker said.
"John's commitment to the game over such a long period of time has been extraordinary and we know that will continue in the future.
"We understand that he also has other commitments and we wish him well in those endeavours."
The decision ends O'Neill's second tenure in charge at the ARU, having led the organisation from 1995 until 2004 before he left to join Football Federation Australia.
He returned to the ARU in 2007 and was instrumental in attracting Robbie Deans to coach the Wallabies after Deans missed out on the All Blacks job.
Deans, however, has been under immense pressure this year as the injury-plagued Wallabies have stumbled through their international season, which began with a loss to Scotland and ended with a second-place finish in the inaugural Rugby Championship.
They also failed to regain the Bledisloe Cup, the symbol of trans-Tasman supremacy, from World Cup winners New Zealand for the 10th successive year.
The New Zealander's grip on the job has been under intense media scrutiny and with O'Neill's departure, speculation will only grow as to whether Deans will still be in charge of the team next year as they prepare for the British and Irish Lions tour in June.
A qualified lawyer, O'Neill joined the ARU just as the game went professional, having spent eight years in charge of the state bank of New South Wales.
During his initial tenure the Wallabies won the 1999 World Cup, captured two Tri-Nations titles and defeated the Lions in 2001.
He was instrumental in organising the highly successful World Cup in Australia in 2003 before he moved to the FFA, where he helped chairman Frank Lowy overhaul the organisation's structure, realigned Australia with the Asian Confederation and launched the A-League.
He returned to the ARU in 2007 and immediately set his sights on Deans crossing the Tasman to build the Wallabies into a side that could challenge for the 2011 World Cup in New Zealand.
O'Neill was a vocal proponent of ensuring a greater revenue share for the southern hemisphere nations from the International Rugby Board and keen on expanding the game outside its traditional power base.
"I am honoured during my second term at the ARU to have played a role in shaping the transformation of the game and I look forward to seeing Australian rugby go from strength to strength," O'Neill said.
"Australian rugby has a rich culture and a proud history, but we have also been working to rapidly modernise and evolve the game.
"I believe the key planks necessary to drive that development are in place, allowing my successor to build on the solid foundations rugby enjoys and take it to the next level of success."
(Reporting by Greg Stutchbury in Wellington; Editing by Julian Linden)