Gold Coast Titans captain Tino Fa'asuamaleaui has lashed out at the decision to penalise Moeaki Fotuaika shortly after halftime in the club's 46 points to 28 loss against the South Sydney Rabbitohs on Saturday evening.

Fotuaika appeared to all but fall off an attempted tackle on Keaon Koloamatangi in the 42nd minute of the game when the Titans were leading by six points.

On his knees, Fotuaika appeared to lose his balance and ultimately landed with some weight on Koloamatangi's ankle, with referee Liam Kennedy, in discussion with bunker official Ashley Klein, electing to penalise Fotuaika, who also ended up on report.

The tackle, which didn't appear to be a hip drop or cannonball, then saw the Rabbitohs score in the following set through returning centre Campbell Graham.

Fa'asuamaleaui labelled the decision frustrating during the post-game press conference.

The captain admitted his side needed to react better to it, but said there was no foul play in the tackle.

"It's frustrating because I was talking to the ref. There was no hip drop, no action where Mo dropped his weight onto his leg. He sort of half slipped off and was already on the ground trying to make the tackle and somehow twisted his ankle," Fa'asuamaleaui said.

"Stuff like that happens in the game and we have to react after it, but it is frustrating when there was no action of a hip drop and no foul play. We have to be better with whatever call happens out there."

The Rabbitohs, who ran away with the game, now sit third on the table with nine wins, while the Titans are just two points outside of the top eight after Saturday's games, but have already used two of their byes.