Premiers Wollongong Bulldogs made it a perfect five successive grand finals in South Coast AFL with a dominant 38-point victory over Kiama Power in Saturday's blockbuster qualifying final at West Street Oval.

The Bulldogs won the vital contested ball and made it two wins in a week over the Power with an emphatic 11.12 (78) to 6.4 (40) triumph.

The Power must respond to only their third loss of the season by beating Northern Districts in Saturday's preliminary final in order to meet the Bulldogs in the grand final for a fourth consecutive year. Norths kept their premiership hopes alive coming from five points down at three-quarter time to beat Bomaderry 10.4 (64) to 7.8 (50) in a torrid elimination final at Tom Smith Oval.

Ken Ewen-Chappell, who signed with Norths on the June 30 deadline, booted five goals, with Adam Carmody kicking two last-quarter goals as the Tigers reversed their elimination final loss to Bomaderry 12 months ago.

Wollongong coach Lee Murray helped found the club initially to play in reserve grade and then in first grade in 2010, and was proud the Bulldogs had made it five grand finals in five top-grade seasons.

"To have that kind of consistency with the turnover of players we've had and all the ups and downs of a footy club it's pretty rewarding to make every grand final since 2010," Murray said.

The Bulldogs lost the 2010 flag decider to Bomaderry before a heartbreak after-the-siren defeat to Kiama in 2011, followed by the maiden premiership in 2012 and a second tight grand final win over the Power last year.

Murray said his team fully deserved their latest win over their arch-rival.

"We were too tough, too strong," he said.

"We won the contested footy which is always crucial in a final and it was a good, solid performance.

"We got away in the second quarter and kept the pressure up right through."

Kiama had the week off last year after beating Wollongong in the qualifying final only for the Bulldogs to run over them in the final quarter of the grand final.

This year the Power have to play the extra week and face the dangerous Norths, whose form has been the equal of Kiama and Wollongong over the last third of the season.

Norths have been building momentum gradually and fought off a gutsy Bomaderry with four goals to one in a pulsating final quarter. Norths led by 17 points at quarter-time but managed just two goals and three scoring shots in the second and third quarters, as Bomaderry turned the screws to lead by five points at three-quarter time.

A desperate Norths rallied in the final term and are now just a win away from making their first grand final since 2008.

Meanwhile, in the reserve grade, minor premiers Ulladulla are through to the grand final following a tough five-goal win over Wollongong.

The Bulldogs now face Figtree in the preliminary final after the Kangaroos eliminated Bomaderry.