Taieri, Southern and Dunedin will join them.
Taieri beat Green Island 36-26 in the 'Battle of the Saddle' at Peter Johnstone Park.
The Grizzlies actually led at halftime but the Eels secured their spot with three second-half tries.
Southern edged Dunedin 19-10 at Kettle Park to book its place. Mackenzie Haugh scored all of Southern's points.
Dunedin progresses courtesy of being the highest-ranked loser and will play Kaikorai at Bishopscourt this Saturday, while Taieri will host Southern in a replay of last year's final.
Kaikorai impressed against Harbour.
The competition frontrunners led 34-0 at halftime and the game was basically over.
Harbour did manage to finish with a flourish. Four second-half tries took some ouch out of the defeat.
The home side was too slick, too polished, and too far ahead at halftime.
They made very good use of all the ball they had in the opening 40 minutes.
First five Ben Miller shovelled it as wide as he could at every opportunity.
His passing and goal-kicking was a real feature.
So was the hustle of openside Lucas Casey. He was a menace, while winger Mefiposeti Tupou hit the ball up with bad intentions.
Lock Oscar Graham has impressed all year and put in another quality shift. Centre Troy Anstiss played with courage.
Perhaps the most pleasing aspect of the performance was the width at which Kaikorai was prepared to play the game. They recycled the ball rapidly as well.
Harbour often found itself stretched and out of bodies.
Casey got the first one. Miller had gone on the outside of the defence to help create the opportunity.
There was some good crisp passing in the move.
Tupou set up the second. He hit it up, bumped off one and got the offload to George Thomas to score.
Hooker Michael Strydom went over on the corner after a quick tap caught the Hawks napping.
And just before the break Graham barged through some weak lineout defence.
The game was effectively over as a contest.
Taylor Dale had a strong game for Harbour at the back of the scrum, but no-one else really stood out.
The scores
Taieri 36-26 Green Is.
Dunedin 10-19 Southern
Kaikorai 54-28 Harbour
Zingari 20-36 AU
