FOR years France had giant lock Olivier Merle, tagged Le Massif Central after the mountainous area in central France, as the backbone of their mighty scrum.

Merle, 41, is no longer an international. But the player who could prove the most dominant force at this World Cup is New Zealand's Highlanders powerhouse, Carl Hayman.

The Dunedin tight-head prop is the wrecking ball of the All Blacks squad. His long, straight back is as rigid as the Southern Alps region from where he hails.

He breaks apart scrums like an oyster farmer splits shells.

Recently retired Wallabies hooker Brendan Cannon said: "New Zealand set the benchmark in scrummaging, and Hayman is such a significant factor for the All Blacks that their scrum loses its potency to a certain degree if he's not there.

"The Wallabies scrummaged really well against the All Blacks this year, but at times there was a momentary loss of concentration. It's a good lesson that the All Blacks worked well in every scrum whereas the Wallaby pack worked well eight times out of 10.

"It's in those two scrums that the All Blacks get a sniff, offering them a chance to put significant pressure on you."

After Hayman, 27, was sin-binned by referee Marius Jonker in the Bledisloe Cup Test in Melbourne this year, Australia scored two tries in eight minutes to transform New Zealand's 15-6 lead into a 20-15 victory.

Hayman was excluded from New Zealand's 2003 World Cup campaign. Graham Henry rectified that omission when he became head coach.

Cup holders England named Phil Vickery and Andrew Sheridan in their team for the warm-up international against Wales this month. They were England's props in the 2005 Twickenham disaster when Australia's scrum crumbled.

That collapse will be foremost in Hayman's mind should the All Blacks meet Australia at the cup.