Sonny Bill Williams is set to announce that he will leave New Zealand Rugby and play in Japan and Australia according to a number of reports.

Williams is said to be on the brink of becoming the highest paid footballer ever in Australia and New Zealand with the potential to earn over $2 million a season.

The Sunday Telegraph says that SBW will announce at a press conference in Auckland on Monday that he will play for the Japanese rugby union team Panasonic on a 10-match deal before returning to Rugby League where he will play for the Roosters.

SBW stands to make $800,000 from the Japanese stint with the rest of $2 million for the year coming from the Sydney Roosters and two boxing matches that he will be permitted to hold.

Williams is believed to be honouring a handshake deal made with the Roosters which started over a cup of coffee in Circular Quay involving the boss of Channel Nine, Williams' agent and SBW himself.

There have been rumours that Williams will not play for the All Blacks in the Rugby Championship which starts next month and there are reports that his name has been seen on a list of registered players in Japan.

SBW is understood to be keeping his options open for the long term as he plans to return to New Zealand Rugby in order to play for the All Blacks at the 2015 Rugby World Cup.