The final round of the Australian Boys' Amateur Championship is set to be a thriller after a third day of contrasting fortunes among the leading contenders.

Ulladulla's Jye Halls, who plays his golf at Mollymook and New South Wales, is still the player to beat at seven under, but his lead has been slashed to a solitary shot after carding a two-over 74 in trying conditions at Gold Creek Country Club near Canberra.

Looming large is Halls' NSW junior state teammate Jeffrey Guan, who carded a respectable two-under 70 to vault into second place.

Nicholas Siegmund, from the Grange in South Australia, is third at five under after an even-par effort, while Toronto's Jake Riley is fourth at three under after the round of the day, a four-under-par 68.

Western Australia's Aldrich Potgieter (-2) and Victorian Nathan Page (-1) are the only other boys who remain under par. Although happy to have kept the lead, Halls was left to rue several lost chances in today's round.

"It was pretty hard," Halls said.

"There was a fair bit of wind, the greens got hard to read and a bit bumpy.

"I had a few three-putts and played a few dumb shots off the tee as well."

Regardless, Halls was still happy to hold the lead and concentrate on what he will need to do in tomorrow's final round.

"I'd rather lead. At least I still have one-shot advantage. I can make a mistake early and still be in contention.

"I won't think about it too much, maybe some pizza tonight, sleep well and come out and hit a few balls tomorrow."

Australian Amateur runner-up Guan wasn't entirely thrilled with his score, but happy to be in the final group and in with a big chance of snaring the national junior crown in tomorrow's final round.

"I hit every green from the 8th, but the putts just didn't want to go in," The Australian member said.

"If I can keep the pressure on Jye, I think I can make some birdies and get to the front," Guan said.

In the Australian Girls' Championship, Victorian Jeneath Wong looks headed for a wire-to-wire win.

Despite carding a two-over 74, the dual Riversdale Cup champion has maintained her four-shot buffer and is the only female in the field in red figures for the tournament.

"I didn't play very good. The greens are getting harder to read," she said.

"I made a few mistakes, missed a few short putts." When pressed about sleeping on the overnight lead, Wong said she wasn't fazed at all.

"I'll just do the same thing I've done every day, keep it one shot at a time."

Wong leads from Perth's Sheridan Clancy, who looked in trouble with two double-bogeys late in her front nine today.

But the Lake Karrinyup member responded nicely with three back-nine birdies to claw back for her own 74.

Queenslander Justice Bosio remains third, but faltered on the back nine today to card a 78 and fall eight behind the leader.

BOYS' SCORES

GIRLS' SCORES