Japan's Rikuya Hoshino fired a flawless 65 Saturday for a share of the lead with Min Woo Lee at the Australian Open, while South Africa's Ashleigh Buhai moved into prime position to defend her women's title.

Six-time Japan Tour winner Hoshino hit four birdies and an eagle to reel in Australian overnight leader Lee in his bid for a maiden DP World Tour win.

Lee began the day in Sydney with a three-stroke lead from Scotland's Connor Syme and American Patrick Rodgers, but struggled with his putter to card a one-under-par 70, holing a pressure birdie at the last.

It set up a re-run of last week's Australian PGA Championship in Brisbane, when Lee took a three-shot lead over playing partner Hoshino into the final day and hung on to win his third DP World Tour title.

"It's one of those days and hopefully I can get it going tomorrow," said Lee. "Today was a bit of a grind, I didn't feel like I had it all there, but still did some good stuff."

Lee opened with a birdie and it looked like he might run away with the lead.

But he found the water at the third to card a double-bogey and another bogey at the 10th coupled with Hoshino's eagle at the 14th put them level at 12-under-par for the tournament.

A birdie for Hoshino at the 18th edged him in front before Lee responded.

"This is the first time I've come to Australia and I am enjoying the atmosphere and the tournament. So that's why I think I'm playing well," said Hoshino.

"I'm going to use many experiences winning in Japan, and my goal this year is to win a DP World Tour event, so I'm going to try my best."

England's Alex Fitzpatrick -- the younger brother of 2022 US Open Champion Matt Fitzpatrick -- surged into contention with a 66 to be one behind them, alongside Rodgers.

The mixed Australian Open involves men and women teeing off in alternating groups on the same courses.

The Australian Golf Club is the main venue across all four days, while the nearby Lakes Golf Club co-hosted play during the first two rounds.

Defending champion Buhai, the 2022 British Open winner, opened her account with four straight birdies, sinking one from the bunker to surge into a lead that she never relinquished.

She kept her focus for a bogey-free 67 to be 12-under for the title, leading South Korean veteran Shin Jiyai, herself a two-time British Open champion, by three shots.

"It would be super special (to win again), said Buhai. "I've heard it's going to be windy (on Sunday) which suits me. I think patience is going to be key."

Australia's world number five and two-time major winner Minjee Lee -- sister of Min Woo Lee -- is third, seven behind Buhai. (AFP)