Australian Rugby Union CEO John O'Neill will stand down at the end of the month, the ARU said on Friday.

The ARU board and O'Neill, who has been a strong supporter of embattled Wallabies coach Robbie Deans, said they had reached agreement to bring forward a departure date originally planned for late next year.

The resignation will allow O'Neill - who has spent almost 14 years in two stints in the role - to concentrate on other business interests, the ARU said.

O'Neill was CEO of the ARU from 1995 to 2004 and stepped down after successfully organising the 2003 World Cup in Australia. He spent three years at the head of Football Federation Australia before returning to the ARU in 2007.

He played a pivotal role in luring Deans from New Zealand to become the first foreign coach of the Wallabies in 2008.

Current deputy Chief Executive Matt Carroll will be acting CEO from next month while a global search is conducted for a long-term replacement, the ARU said.

ARU Chairman Michael Hawker said O'Neill had been a wonderful and committed contributor to the game over a long period of time and was stepping down after having laid the foundation for an important evolutionary phase for Australian rugby.

"John's workload beyond rugby has recently grown significantly and unexpectedly," Hawker said.

"John had previously indicated he was standing down when his contract ended next year, so the timing of his resignation is now logical for both him and the ARU.

"Under his leadership, a Governance review into the game has been initiated; planning for the 2013 Lions Tour is well underway; the Wallabies have improved from fifth in the world when John returned to the game in 2007 to now second behind the All Blacks; participation levels are at an all-time high; the ARU has strengthened its financial position; we have increased influence at the International Rugby Board; Rugby has been further expanded with a fifth team in Melbourne; and the new Rugby Championship has been launched with the inclusion of Argentina, refreshing the Southern Hemisphere Test competition.

"John has been a great servant of Rugby in Australia over two decades and has achieved the key objectives of a five-year strategic plan since re-joining the ARU in 2007.

"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."

While O'Neill is standing down from an executive role at ARU, he will continue to serve as an ARU delegate to the International Rugby Board, as Chairman of the IRB Regulations Committee, and as a Board member of Rugby World Cup Ltd, the ARU said.

His Rugby World Cup Ltd appointment, through to 2016, is in a personal capacity.

After a celebrated 18-year career in sports administration, O'Neill said Rugby was positioned for a bright future.

"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.

"There are other challenges for me to pursue outside the game now, although my involvement at an IRB and Rugby World Cup Ltd level will ensure I have a strong ongoing connection."

Hawker said O'Neill would be remembered as one of Australia's great sporting administrators.

"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," said Hawker.

"We understand that he also has other commitments and we wish him well in those endeavours.

"The ARU has a big agenda and there is much still to be done to strengthen the game.

"We will be seeking another world class sports administrator who can deliver the ambitious plans we have for the future of Rugby in Australia."