Greg Norman, bidding to win his sixth Australian Open, believes finesse rather than power will decide the winner of this week's tournament at the Metropolitan course in Melbourne.

Australia's world number one, who is up against Ryder Cup duo Lee Westwood and Darren Clarke, American pair Phil Mickelson and Mark Calcavecchia and Fiji's Vijay Singh, said shot placement and club selection will be critical.

The championship layout has undergone radical changes as officials act to combat advances in golf technology.

The decision to remodel Metropolitan is part of a worldwide move to toughen traditional courses which have become prey for fitter players aided by space-age materials in clubs which propel the ball further.

"It's not a golf course you can overpower. Not all the old bunkers come into play any more, but you still can't rip it apart," he said.

"When we were younger, we used to go for the green at the (par four) 17th, but you can't do that any more."

Norman said he expected a score similar to the winning aggregate in recent years to again be successful.

"The scores around here have always stayed pretty much the same, around 12 or 14 under par, but if we get wet and calm days the guys could shoot 18 or 20 under. But we seldom have four calm, moist days," he said.

American left-hander Mickelson gave a more cautious prediction after his first look at the Metropolitan layout: "I think it's going to be a great test of golf. I'd be surprised if even par wasn't right around the lead."