SYDNEY, Nov 16 - Nathan Green defied the wind and rain to shoot a five-under-par 67 that gave him the clubhouse lead in the first round of the Australian Open on Thursday.

The 31-year-old Australian offset a single bogey with six birdies to open a two-stroke advantage over compatriots Jarrod Lyle and Richard Green with Steven Bowditch a further two shots behind.

A torrential downpour and gusting winds at Royal Sydney made low scoring difficult, with most players battling just to make par and avoid dropping shots.

"The conditions were tough," the leader told reporters. "On a day like today you just try and keep it in play."

Australia's U.S. Open champion Geoff Ogilvy finished the day level on 72 while PGA Tour championship winner Adam Scott was two-over with three holes to play.

"It's hard work, but I didn't do too much damage. The idea is to not be out of the tournament on a day like this," Ogilvy said.

"There will be a lot of guys out there who'll be out of it by the end of today."