Former Wallaby Giteau retires at 40 after 'milking' contracts dry

Former Australia flyhalf Matt Giteau has announced his retirement from professional rugby at the age of 40, joking that he had "milked" the game dry.

The 103-test Wallaby last played for the Major League Rugby team LA Giltinis who folded last year.

"It's been such an amazing experience & one that I will miss but I have milked this game and contracts dry," Giteau wrote on social media.

Part of Giteau's legacy will be felt long after his retirement, as the player associated with Australia's relaxation of its long-held ban on selecting overseas-based players for the Wallabies.

The so-called "Giteau Law" was championed by Michael Cheika to allow the former Wallabies coach to select him for the 2015 World Cup in England when he was playing in France.

In the last of his three World Cups, Giteau played a key role in the Wallabies' run to the final but suffered a head knock in the opening minutes of the 34-17 defeat by New Zealand.

The tough and versatile back's last test was a thumping 42-8 loss to the All Blacks in Sydney in 2016.

Giteau won seven elite competition trophies across the globe, winding down a two-decade career with stints in Japan and the United States.

"Half my life spent playing this great game professionally and travelling the world getting to do it. Forever grateful to all my many coaches, staff members, referees and touch judges along the way," he said.