Australian golfer Lucas Herbert says his caddie is "good now" after he was struck in the head by a water bottle during second-round action on Saturday at LIV Golf Adelaide.

Herbert had just made birdie on the 12th and was celebrating with boisterous fans when his caddie - Nick Pugh - was hit in the back of the head by a water bottle thrown by a patron while replacing the flag in the cup.

Pugh was knocked to his knees but managed to avoid serious injury. He eventually made his way back to the clubhouse at The Grange's Golf Club.

"I was worried about him to begin with, but he's good now," said Herbert told the Sydney Morning Herald after his round. "He's good and he took it really well. He could have been a lot more upset with it, but he took it really well."

More than 30,000 fans were in attendance for LIV Adelaide's second round, many of whom were crammed into the popular party hole.

"It's probably difficult to request someone who has had 15 beers to aim a water bottle away from someone," added Herbert. "That's maybe asking too much.

"[Playing partner] 'Gracey' [Branden Grace] made a putt from the top tier and some drinks landed on the green. That's good fun, and it's in the right spots so we can deal with it. A few pushed it too far. But the crowd self policed and they got some boos when they were throwing things too close. That's about as crazy as it needs to get."

Fans on the 12th had been well-behaved during the first two rounds of play until Saturday's incident.

Chase Koepka was showered with beer cups when he made a hole-in-one on the 12th during the final round last year.

Australian Open champion Joaquín Niemann said he has no issue with the fans at the watering hole.

"It's crazy. You get there and you can barely talk with your caddie," Niemann said. "It is fun. I get there and you're feeling a bit more pressure having all the people watching you."

Herbert carded a 7-under 65 on Saturday, but he's seven shots off the lead of American Brendan Steele who sits atop the leaderboard at 14-under.