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For once, Kangaroos captain Darren Lockyer is worried the Benji Marshall-inspired Kiwis have got the jump on his "rusty" side for Sunday's World Cup rugby league opener here.

Lockyer, Kiwis captain Nathan Cayless and the eight other skippers assembled today at the Sydney Football Stadium to officially begin the tournament countdown.

The Kangaroos' playmaker saw footage of the Kiwis' impressive 56-8 win over Tonga on Saturday, their second warmup match together as they flew into Sydney last night in confident mood.

Meanwhile the Kangaroos assembled at their Sydney beachfront hotel at the weekend and go into the tournament as $1.20 favourites, without a warmup match. Even a likely dominance of Queensland players, including Lockyer and Johnathan Thurston in the halves, wasn't filling the captain with confidence.

"It makes it easier, but at the same time we haven't played together for a while and we are going to be a bit rusty, not just some combinations, but everyone," Lockyer said.

"We want to set a bit of a precedent with our performance and we want to play tough, but I just can't see us having a polished performance this week because it's going to be our first game together."

Lockyer said the players probably wouldn't be told their playing 17 by coach Ricky Stuart until tomorrow.

It's the reverse of the trend in the annual April/May tests, with the Kiwis only having a few days to establish combinations and usually suffering a trans-Tasman thrashing.

Lockyer said the Marshall factor was giving him the most reason to be wary of the Kiwis, rated $6.50 tournament second favourites ahead of England.

Marshall stamped his authority on Saturday's game, showing his wide range of attacking skills and crossing for two of the Kiwis' 10 tries.

"I saw some of the highlights and it looked like Benji had a good game. When he's confident he's a pretty dangerous prospect.

"Their defence looked like it was in order. Knowing Wayne (Bennett) and (coach) Steve Kearney, they'd be pushing to make sure their defence is where it needs to be."

Lockyer said the focus would be on a dominant forward performance and defensive pressure on Marshall and halfback Thomas Leuluai to halt the ad-lib, second phase football the Kiwis were most dangerous at.

There was also the undeniable impact of Bennett, Lockyer's former Broncos coach, as the Kiwis' technical adviser.

"Wayne's always made his players believe in themselves and with Benji at the moment, he's playing some good football and there's probably a number of other guys that's he's keeping in a positive frame of mind. That's going to make them play better."

The Kiwis will train at Marshall's Wests Tigers base at former test rugby venue Concord Oval all week, with Kearney scheduled to name his team on Wednesday.