The second and third rounds were both completed Saturday. The second round had a two-hour weather delay on Friday and was eventually suspended for the night due to darkness.
Ter-Chang Wang, one of four first-round leaders, shot 2-under 70 in the third round and is alone in third place at 12-under-par 204.
Stephen Dodd, who fired a 63 in round two to lead at the halfway point, struggled to a 2-over 74 in the third round. He slipped back into a tie for fourth at minus-10, where he was joined by Shiv Kapur (66), David Higgins (69) and Thongchai Jaidee (72).
Wang, playing in the penultimate threesome, eagled the par-5 first to jump to 12 under and a share of the lead with Dodd. Dodd parred the first, while Dyson, his playing partner, converted a 20-foot eagle putt on the opening hole to create a three-way tie for the lead at minus-12.
Dyson came right back with a 12-foot birdie putt on the second at Emeralda Golf & Country Club to grab the lead. He pushed his lead to two strokes over Jaidee with a birdie on the fourth.
A bogey by Jaidee on the fifth gave Dyson a three-stroke cushion. Dyson's lead slipped to one though as he bogeyed the ninth to fall back to 13 under.
Meanwhile, Buckle opened with three straight birdies from the first to jump to 11 under. He birdied the 10th to get within one of Dyson. Dyson briefly stretched his lead back to two shots as he birdied the 12th.
The 23-year-old Buckle birdied the 14th to get back within a shot. The Australian then birdie No. 16 to join Dyson atop the leaderboard. Buckle made it two straight as he birdied the 17th to take a brief lead.
'I'm playing well. I hit a couple of shots off line, but managed to get out of trouble,' Buckle said. 'I'm putting well which is the main thing. I'm just going to give it my best shot Sunday and see what happens.'
The 28-year-old Dyson joined Buckle at minus-17 with a birdie of his own at the 17th. He also parred the last to share the third-round lead.
'I just want to keep playing as I have been doing and shooting sub-par rounds,' said Dyson, who won three times on the Asian Tour in 2000. 'I think if one of us shoots 4- or 5-under on Sunday, it could take it. I am looking forward to it. I have been in a share of the lead every day and feel I have responded well.'
After his eagle at the first, Wang tripped to a bogey on the third to slide back to 11-under. He parred his next 11 holes before a birdie on the 15th got him to 12-under. Wang closed with three more pars to end three back.
Wei Chih Lu fired a 6-under 66 Saturday to climb to 9-under-par 207. He shares eighth place with Matthew Millar, Rahil Gangjee and Peter Gustafsson.
Thaworn Wiratchant, the 2005 champion, carded a 71 in the third round. He shares 21st place at 6-under-par 210.