Popovic has picked up four shots to move from eight to 12 under par after 10 holes, with Aussies Mathew Goggin and Matthew Griffin on the move at seven under.
Geoff Ogilvy's charge has stalled on six under through nine holes.
Leading progressive scores from the second round of the Australian PGA Championship at Palmer Coolum Resort Golf Course today (a-denotes amateur, par-72):
-12: Daniel Popovic (AUS) 11 holes
-7: Mathew Goggin (AUS) 11 holes, Matthew Griffin (AUS) 8 holes
-6: Geoff Ogilvy (AUS) 9 holes, Scott Strange (AUS) yet to play
-5: Tze-huang Choo (SIN) yet to play, Xin Jun Zhang (CHN) yet to play, Steve Conran (AUS) 13 holes
-4: Ryan Haller (AUS) yet to play, Stephen Dartnall (AUS) yet to play, Peter Senior (AUS) yet to play, Jason Scrivener (AUS) yet to play, Rory Hie (SIN) 8 holes, Adam Crawford (AUS) 14 holes, Jason Kang (USA) 8 holes, Leigh McKechnie (AUS) 9 holes