Barry, riding his fourth Tour of Southland, eventually took the stage win by the slimmest of margins, but he was equally concerned by ensuring Northey remained within touching distance of yellow.
"After losing the yellow jersey, we had to use today to try and get Mike (Northey) back up there," Barry said.
"We just wanted to put the Bissell guys under pressure so when [the peloton] started splitting I went across and put us in a good position for Mike to have an easier ride."
Jones, 23, finished the stage more than two minutes back from Barry and Roulston but, while his Tour lead has narrowed, he is still sitting in yellow ahead of the final day.
Bissell manager Glen Mitchell was confident Jones, who will have the advantage of starting tomorrow's time trial last, had the ability to take the yellow jersey all the way.
"We need these guys to put in the best time trial they can," he said. "I'm confident in Carter's ability, he definitely time trials very well. I don't think he will lose any time, he could even gain a little bit. The guys have got six days of racing in their legs, so you get to a time trial and that's pretty crucial."
Sam Witmitz secured the sprint ace jersey after another good day and the king of the mountain jersey sits comfortably with Joe Chapman. Taylor Gunman has a 1m38s lead in under-23 classification and Node 4-Subaru leads the team classification after another strong day.
Results from stage six of the Tour of Southland today:
Daniel Barry 3:51.56, 1; Hayden Roulston same time, 2; Clinton Avery +34s 3; Michael Vink +1:35, 4; Heath Blackgrove +1:37, 5; Michael Northey +1:37, 6; David Clark +2:02, 7; Pieter Bulling +2:02, 8; Sean Hambrook +2:02, 9; Taylor Gunman +2:02, 10.
General classification standings:
Carter Jones 19h18m49s, 1; Michael Northey +4s, 2; Taylor Gunman +48s, 3; Daniel Barry +1:32, 4; Hayden Roulston +1:58, 5; Heath Blackgrove +2:10, 6; Sean Hambrook +2:26, 7; Michael Vink +2:39, 8; Gordon McCauley +3:01, 9; David Clark +3:10, 10.
