Malaysian duo Gavin Green and Ben Leong took advantage of calm morning conditions during a nine-under-par 63 at Metropolitan Golf Club on Thursday during the four-ball (best ball) format before it was matched Belgium (Thomas Pieters and Thomas Detry).

Joining Malaysia and Belgium atop the leaderboard are England stars Tyrrell Hatton and Ian Poulter, as well as defending champions Denmark (Thorbjorn Olesen and Soren Kjeldsen) and Korea (Si Woo Kim and Byeong Hun An).

However, Leishman and Smith are just one shot back midway through the back nine having birdied the par-4 13th and par-5 14th.

Earlier, the pair were doing their best to live up to tournament favouritism with an eagle and four birdies to make the turn at six under.

Also at eight under courtesy of a 64 are Irish pair Shane Lowry and Paul Dunne.

Making his World Cup debut, unheralded Malaysian golfer Leon said having experienced countryman Green by his side was comforting.

"Gavin calmed me down after I was really nervous on the first hole, so that was great," said Leong.

Green says the pair had no expectations for the unofficial $US7 million ($A9.6 million) PGA Tour event that sees 28 two-man teams contest two rounds of four-ball and two rounds of foursomes (alternate shot).

"I don't know if we flew under the radar but we definitely just thought we wanted to come down (to Melbourne) and have fun," Green said.

Australian Associated Press