Chris McKenna has sounded an ominous warning: Australia aren't even playing that well.

That doesn't say much for deflated Great Britain, whose humbled players will be watching the Tri-Nations final from home tomorrow.

British rugby is taking another long, hard look at itself following more failure on the international scene and instead it's the Aussies doing battle against holders New Zealand in a rematch of last season's showpiece.

But the Bulls' former Kangaroos star reckons the expectant hosts and favourites have also yet to impress ahead of the Sydney showdown.

"Australia haven't really been playing that well," said McKenna.

"They've been stumbling and bumbling along more than anything but have got to be at their best tomorrow to knock New Zealand off.

"There isn't much speed or urgency to their stuff at the moment. If they can find that we'll blow them away like we did against Great Britain over here a couple of years back."

Second-rower McKenna, who made the first of his two Test appearances against New Zealand six years ago, admits losing against the Kiwis on home soil would be unbearable for his fellow countrymen.

Gutted Australia have already endured a painful 12 months since the shock 24-0 hiding at their hands in last year's final.

"It would be hurtful to lose again but I don't think it will happen," he said. "I do think Australia will come good."

New Zealand, with Bradford's Shontayne Hape on the wing, are confident though, having nearly won in Melbourne five weeks ago before a sensational late finish saw Australia sneak home.