Sonny Bill Williams’ return to the boxing ring has been given the All Blacks’ green light although they hope his opponent is no gun.

Dual code international Williams is likely to fight over the off-season, probably in late January, before he begins his Super Rugby campaign with the Chiefs.

Former New Zealand heavyweight champion Williams hasn’t fought since beating South African Francois Botha in Brisbane nearly two years ago, a sixth win from six bouts.

The 29-year-old’s manager Khoder Nasser included a clause to box in Williams’ contract when he re-signed this year with the Chiefs and NZ Rugby.

All Blacks coach Steve Hansen gave Williams his blessing, noting that more top sportsmen are entering the ring for its wider benefits.

“He’s a guy who finds boxing is good for his fitness and the Chiefs are happy for him to do it,” Hansen said.

“My only words of wisdom to him will be: ‘Don’t find anyone who can beat you’.

“Khoder’s pretty sharp – he’s not going to put him in against someone who’s going to knock him around.”

Williams started three of the four tour Tests and came off the reserves bench against Scotland, exceeding expectations with an imposing return at inside centre after two seasons in the NRL.

He blotted his copybook in the 34-16 win over Wales, however, routinely losing the ball and being outplayed by opposite Jamie Roberts. He was replaced before the All Blacks launched their late heroics.

Williams’ rapid return was fast-tracked by the broken arm suffered by veteran No.12 Ma’a Nonu midway through the Test season.

The duel between the two high-profile backs for a starting spot next year should be one of the highlights of 2015.