Sonny Bill Williams believes England have erred by picking fellow code-hopper Sam Burgess in the centres for the Rugby World Cup, insisting his best position is flanker.

Burgess, the Clive Churchill medal winner from South Sydney’s NRL premiership win last season, was on Monday picked on the bench for England’s World Cup opener against Fiji.

Like Burgess, Williams was a barnstorming forward in rugby league and has made a success of playing in the backs in the 15-man game.

However, the All Blacks centre insists Burgess is destined for the forwards in rugby, pointing to his impressive performance in Bath’s loss to Saracens in the Premiership final – lauded as the 26-year-old’s finest match in his new code.

Based on that, Williams insists Burgess would have a greater impact there than in the centres, where he played his only international match so far and where he is expected to feature against Fiji.

“(It’s a) massive achievement, really proud of Sam,” Williams said of Burgess’ selection.

“He’s a good man and I know that he will handle it with ease, he just needs time in the saddle.

“For me personally, after watching his games… don’t get me wrong he goes really well at centre, but I think his prime position in the future will be on the side of the ruck.

“The final that he played in, I thought he played awesome.”

Despite being played out of position, Williams was confident Burgess will find a way to impose himself on games.

And should England escape the ‘pool of death’ and set up a knockout clash with New Zealand deeper in the tournament, the two-time NRL premiership winner said he would be keeping his distance from Burgess’ powerful shoulder which left several French defenders feeling worse for wear on his England debut last month.

“I’m sure, the type of talent that he is, he will handle that midfield role with ease,” Williams said.

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

The Wallabies will get a shot at Burgess and England when the Pool A rivals do battle at Twickenham on October 3.

Australia, meanwhile, quietly continued their preparations after landing in London on Monday following a pre-tournament camp in the USA.

They immediately travelled to Bath, where coach Michael Cheika will fine-tune the squad ahead of their opening clash with Fiji in Cardiff on Wednesday week.