Smith is regarded as a solid slips fielder but grassed a catch that could see Pakistan claim a world record-breaking victory at the Gabba as they chase 490.

They finished day four with figures of 8-382.

Asad Shafiq (100 not out) was dropped on 72 on Sunday night by Smith off Mitchell Starc.

He then dropped Sarfraz Ahmed on 19 off Josh Hazlewood before he was bowled by Starc for 24.

"He's obviously a very good slips fielder and he dropped two catches that he usually takes," Australian assistant coach David Saker told AAP.

"It was a bit frustrating in the dressing room.

"You wouldn't have wanted to be in the room with (head coach) Darren (Lehmann) and I going off."

Smith somewhat redeemed himself after taking Wahab Riaz (30), his third catch of the innings.

"He ended up taking a good one at the end which was a pretty important wicket in the context of the game," Saker said.