BACK AT WORK: Israel Folau, at Waratahs training on Thursday, wants to move from fullback to centre.

He was denied the chance last year but Israel Folau still harbours ambitions for an audacious midfield switch on the eve of the Waratahs' Super Rugby title defence.

Folau has long dreamt of adding the No 13 to his rugby repertoire and believes it will give him more opportunities to contribute in attack and defence.

A move was on the cards last year, but Waratahs coaches Michael Cheika and Daryl Gibson opted to keep their dual international at fullback, a decision no one could question given the southern hemisphere's most prized piece of silverware now adorns the trophy cabinet at Moore Park.

But last year's success appears to have fuelled Folau's hunger. In his first interview since returning to training this year he told Fairfax Media he hoped to keep the pressure on his coaches for a possible switch later this year.

"It's something I see as a little bit similar in attack to what I played as a centre in league - running lines and getting in amongst it, the ball in hand, close to the action - that's something that really excites me," Folau said.

"But that's only one element, the other area is defence, and at set piece. I'm willing to take up the challenge.

"We spoke about it last year, we haven't spoken about it this year, but it's something I keep in the back of my mind. I'm open to it and I've played wing before, so it would be good to have a whole different bag of skills where you could play in different positions for the team."

A looming showdown with fellow league convert Sonny Bill Williams may be keeping it front of mind for Folau. Williams is back with two-time Super Rugby champions the Chiefs for his second stint in rugby after two seasons and one NRL title with the Sydney Roosters.

The 2011 World Cup winner resumed his midfield partnership with veteran All Blacks No 13 Conrad Smith and will travel to Sydney with his province for a Friday night trial match against the Waratahs on February 6.

It will be the first time Williams and Folau stand face to face on a rugby pitch. The Waratahs fullback is relishing the prospect.

"All the different codes he's played and the boxing as well, he's been around and he's a quality player so it will be a great challenge," Folau said, adding that he believed it would be the first time they have played against each other since a Storm-Bulldogs showdown in 2007.

"He was one of the danger men we looked at during the week going into those games. He's dangerous with the ball in hand and can get second phase plays out with his offload."

Williams returned to New Zealand after last year's NRL season wrapped up and was drafted straight back into Steve Hansen's All Blacks for the test side's spring tour. He capped his return with two tries against the United States and started two more tests on tour.

Folau paid tribute to his rival's impact on the code since his switch in 2011.

"He changed the game around with the offload and the way a No 12 plays," he said.

"He's strong, and he's quick for his size as well, with pretty good skills for a big guy. He did really well when he played the game."

Folau laughed off suggestions he could find himself in the running for the Wallabies No.13 jersey come September, when the World Cup kicks off, but said his rationale for some positional experimentation was adding more to his attacking repertoire.

"I'm usually out in those wider channels getting the ball and maybe just finishing off the plays, whereas I want to get a bit closer, get my hands on the ball and get a second touch so I can add that on to what I can do out wide," he said.

"A positional change would add a little bit more to the attacking side of things, which for me would mean I'd have a lot to offer."