SBW hangs up boots and laces up gloves

Former All Black Sonny Bill Williams has confirmed his rugby career in both league and union is finally over.

The 35 Williams has told Nine News in Sydney that he now wants to focus on becoming a world champion boxer.

Williams finishes his NRL career having played 123 first grade games between the Bulldogs and Roosters, with premiership wins at both clubs in 2004 and 2013.

He will however continue to be involved with the Roosters in a mentoring role.

Williams played 58 times for the All Blacks.

Williams told Nine News he hopes to go into his next fight, whoever that may be, with "six months" of training and not "six weeks", which was the case during his career as a footballer.

After returning to the Roosters at the end of last season on a short-term deal, Williams has now built a gym in Sydney as he pursues real boxing success.

I spoke to my manager, I said 'bro I'm keen to get back into the ring, I've got a couple of years, I'm 35'," he said.

"I spoke to the wife first and she had blank eyes but like usual, she supported me."

"I want to know how I will go in six months instead of six weeks."

Williams admitted an ongoing knee injury meant he didn't believe he was up to playing on.

"I was humble enough to understand my knee couldn't meet the demands although the mind wanted to of the week in and week out footy, especially in the NRL.

Asked how he wants to be remembered in rugby league, Williams said: "As a brother and a man that just gave it a crack.

"Wasn't perfect by any means but tried to learn from his lessons."