South Sydney Rabbitohs inflicted more pain on the beleaguered Brisbane Broncos despite the absence of Wayne Bennett with an emphatic 28-10 victory in the rain at ANZ Stadium.

Broncos coach Bennett was forced into isolation for two weeks on Thursday after breaching the NRL's biosecurity protocol with a trip to a restaurant.

The Bunnies were clearly not affected by Bennett not being present for the clash with his former club on Friday as they moved up to sixth place, with Jason Demetriou filling in as coach.

Dane Gagai finished off a well-worked move to put the Rabbitohs in front and although the Broncos responded with a score from Herbie Farnworth, Adam Reynolds and Mark Nicholls crossed to give the home side a 20-6 half-time lead.

The fit-again David Fifita marked his return from injury with a try to give the second-bottom Broncos hope, but Tom Burgess finished at the other end and Reynolds made it four conversions out of four to complete the scoring.

It was another day to forget for Brisbane, with club legend Allan Langer earlier among three staff members to be stood down for breaching COVID-19 protocols.

New Zealand Warriors earlier ruined Manly Sea Eagles boss Des Hasler's 400th game as an NRL coach with a 26-22 victory at Lottoland.

Patrick Herbert grabbed a double as the Warriors got off to a storming start, leading 16-0 after 18 minutes, before withstanding a Manly fightback to move up to 11th.