All Black Sonny Bill Williams says England are using his fellow code-crosser Sam Burgess in the wrong role and that the English powerhouse would be better deployed as a flanker.

England coach Stuart Lancaster has the rugby league convert pencilled in as an inside centre for the World Cup hosts, but Williams believes that is an error.

“Don’t get me wrong, I think he goes really well at centre, but Sam’s prime position in the future will be at the side of the ruck,” he told Britain’s Daily Telegraph.

Williams, a dual code international and former WBA heavyweight boxing champion, said Burgess’s performances for club side Bath in the back row suggested that was where his future lay.

Wherever Burgess features, though, the All Black sees him making an impact.

“He just needs time in the saddle,” Williams said. “I’m sure, with the type of talent he is, that he will handle the midfield role with ease.

“I hope that if we do come up against him, we stay away from that shoulder of his.”

Burgess is widely seen as England’s answer to Williams -- a big ball-playing rugby league forward who can transfer those skills to the backline midfield in union.

He switched from Russell Crowe’s South Sydney Rabbitohs to English club Bath in December 2014 and made his England debut in the 19-14 win over France last month.

Former England players including Will Carling and Matt Dawson have questioned his tactical nous in union and argued that he was not ready for a World Cup, but Lancaster has put his faith in Burgess as an impact player from the bench.

The 26-year-old Yorkshireman has been named among the replacements for England’s World Cup opener against Fiji on Friday evening.