Wayne Bennett has the chance to claim his eighth premiership as a coach, after South Sydney defeated Manly 36-16 to reach its first grand final since 2014.

Bennett, who won six premierships with the Broncos and another with the Dragons, watched on at Lang Park on Friday night as the Rabbitohs dominated the Sea Eagles in their preliminary final.

The Rabbitohs will face either the Melbourne Storm or Penrith in the grand final on October 3.

They scored seven tries to three against the Sea Eagles, with Cody Walker, Alex Johnston and Jaxson Paulo all posting doubles.

Fullback Blake Taaffe, who assumed goal-kicking duties from Rabbitohs captain Adam Reynolds, landed four conversions.

Reynolds, who is joining the Broncos next season, was troubled by a groin strain during the match.

The victory earned Bennett, who will depart as Rabbitohs coach at the end of the season, a 10th grand-final appearance.

He will be the first to coach four different clubs in a grand final and potentially the first to win with three different clubs.

The Rabbitohs are chasing their first premiership since their most recent grand final seven years ago.

Manly's bus was stuck in traffic in a delay that pushed the match back 15 minutes and the Sea Eagles' night did not improve.

They were denied two tries in a first half that saw them with just 36 per cent of the ball.

Walker opened the scoring for the Rabbitohs in the 12th minute, before Manly winger Reuben Garrick had a try disallowed because of an obstruction.

The Rabbitohs crossed again through Johnston in the 22nd minute, with the two tries converted by Taaffe.

Tom Trbojevic had put Garrick over for the first disallowed try and the Manly fullback then had one of his own turned away, when he spilled the ball with three desperate Rabbitohs clinging on as he fell over the line.

Rabbitohs hooker Damien Cook set up Walker's second try, before Paulo's first four-pointer made it 22-0 at half-time.

A Manly comeback was given life when Garrick scored first after the break, but that was snuffed out when Campbell Graham barged over.

Rabbitohs fans, who made up the bulk of the 26,249-strong crowd in Brisbane, could relax when Paulo back-peddled almost 10 metres to the line after catching a Reynolds bomb to score in a fashion that even had Bennett smirking.

Late frustrations showed when Manly's Josh Aloiai was sin-binned for a dangerous tackle.

Trbojevic did have some joy with a runaway try — his 28th this season — in the 73rd minute.

Garrick and Johnston both completed try doubles in the shadows of full-time.

AAP/ABC