Sonny Bill Williams cast doubt on his future with the All Blacks on Monday, saying he would not make a decision on whether to remain in New Zealand until after the World Cup.

In the latest twist of a long-running saga over Williams' future, the Rugby League convert said all options were on the table, including a possible move overseas that would make him ineligible for All Blacks selection.

"I don't want to make a hasty decision," he told reporters.

"People have been pushing me to make a decision, but for me it's about doing what's best for myself and my family.

"I've just got to assess the situation after the World Cup. At this stage, I'm trying to push everything away and make everything else irrelevant and just solely concentrate on rugby."

Williams' stance is at odds with comments made by his Australia-based manager, Khoder Nasser, who said last month that the player felt a "moral obligation" to stay in New Zealand for at least another year.

"A man is entitled to change his mind from time to time," Williams said when quizzed about the backflip.

"I've spoken to [Blues coach] Pat Lam and [incoming Chiefs backs coach] Wayne Smith and told them how I'm thinking, so everything is all good."

The 26-year-old walked away from a world-record US million offer from the French club Toulon to move home to New Zealand last year on a short-term contract, in the hope of making the All Blacks World Cup side.

While he made the 30-man World Cup squad, Williams has found himself playing second fiddle to centre rival, Ma'a Nonu, whom coach Graham Henry last week described as "the best No.12 in the world".

Williams could not even make the bench for the New Zealand side that lost to Australia last Saturday, but denied the non-selection was behind his reluctance to sign a new contract with the New Zealand Rugby Union (NZRU).

"Not being in the squad has definitely not played a part," he said.

"I just don't think it's right that I make a hasty decision and that's what I would be doing."

The NZRU and Nasser are reportedly at loggerheads over a demand that the player receive compensation for a product endorsement that fell through after the sporting body vetoed it because a rival product sponsors the All Blacks.

Australian boxer Anthony Mundine, a close Williams ally who is also managed by Nasser, criticised the All Blacks coaches on Twitter last week and suggested there was an agenda against the player.

AFP