North Queensland Cowboys beat South Sydney Rabbitohs 20-0

South Sydney's NRL season is all but over after a toothless 20-0 defeat to North Queensland extended their losing run to five.

The Rabbitohs rarely fired a shot at the defending premiers in front of a strong crowd at Barlow Park in Cairns, who instead watched Cowboys skipper Johnathan Thurston put on a signature clinic.

The Queensland State of Origin star scored a try and had a hand in another, helping the visitors consolidate their spot in the top four before getting a well-deserved early mark in the 75th minute.

For the Rabbitohs however, the defeat continues their miserable 2016 campaign and leaves them with the near-impossible task of winning all eight of their remaining games to make the finals.

Led by James Tamou and Matt Scott, the Cowboys forwards strolled through the Rabbitohs middle with concerning ease, paving the way for Thurston and company to ruin John Sutton's 250-game celebrations.

Greg Inglis and Luke Keary tried hard for the visitors, as did Sam Burgess, although the star forward succumbed to a knee injury midway through the second half.

The game started horribly for the home side after winger Joe Burgess was trapped in his in-goal following Kyle Feldt's trademark towering kickoff.

From there it was all the Cowboys, who used a 65 per cent possession rate in the first half to lay on tries for Thurston and Scott and take a comfortable 14-0 lead at the break.

A try to Javid Bowen, deputising for the injured Kane Linnett, kicked the advantage to three tries early in the second half before the Cowboys closed out the match by keeping an opposition side scoreless for the third time this year.