Kaikorai beat Taieri 22-15 at Bishopscourt today keeping the positions on the Dunedin club rugby leaderboard competition close.
Kaikorai pulled away in the second half to win to affirm its spot in the top four.
Harbour got back on track after its first loss last week and consigned Southern to its second straight defeat.
Southern was never in the game at Watson Park and lost 37-7.
Dunedin caused an upset with a 19-15 win over University, scoring a try late on, while Green Island beat Zingari-Richmond 47-10 at Montecillo.