Campbell, who opened the tournament with rounds of 66 and 68, carded a one-over 73 at Nudgee Golf Club on Saturday to be nine under heading into Sunday's final round.
Smith, who is three shots behind and well placed to make a charge on Sunday, looms as Campbell's biggest threat.
The 2022 British Open winner had a low-key Saturday, mixing three birdies with two bogeys in a one-under 71 for a three-round total of 210.
Defending champ Phoenix Campbell has a one-shot lead at the Queensland PGA Championship. (HANDOUT/GOLF AUSTRALIA)
Smith will at least be riding some momentum heading into the final day, after finishing his third round with three birdies in the final four holes.
"I did what I had to do today," Smith said."I feel like I did a lot of things right today, especially on that front nine. Just couldn't get anything going and couldn't get any putts to drop."I was hitting the ball great and then holed a couple of putts at the end."
Smith's six-under total gives him a share of fourth place with fellow Australian Billy Dowling, who had a Saturday he would rather forget, carding a three-over 75.
At one stage Campbell was sitting pretty at 10 under with a six-shot buffer over Smith, but a double-bogey six on the par-4 16th slowed his momentum, before a birdie on the par-3 18th sent him to the clubhouse at nine under.
After two days playing in front of Smith, Campbell was in the group behind on Saturday and hopes to draw a few more fans back from "Cam's caravan" of followers on Sunday."I didn't feel like the main attraction today. I definitely wasn't, despite leading the tournament,'' Â Campbell said.
The crowd loved that Phoenix 🤩— PGA of Australia (@PGAofAustralia) #QldPGA | #TheChaseIsOn pic.twitter.com/WamIPXo4GgNovember 2, 2024
"It's a different vibe. It's really cool to see so many people out and hopefully tomorrow there'll be more people out again."I'm really looking forward to using the energy of the crowd."I play my best golf on Sunday, so I'm really excited to get going. I feel like I can lift and play my best golf tomorrow."
Campbell has a one-shot lead over South Australian Jak Carter, who followed 71s in the opening two rounds with a brilliant six-under 66 on Saturday for a three-round total of 208.
Carter's impressive round on Saturday featured an eagle, five birdies and just one bogey.
Alone in third place is New Zealander Kerry Mountcastle, who fired the day's best round of eight-under 64 for a three-round total of 209.
Mountcastle needed something special on Saturday after opening with rounds of 71 and 74. He certainly delivered the goods, with nine birdies more than compensating for his one bogey.