Mid Northern scored the first points of the match through winger Lote Palaih.
After winning the lineout, hooker Jordan Olsen made a break then handed the ball off to Palaih to open their account.
Kamo hit straight back through a penalty off the kickoff.
First five Tom Herman slotted the goal, bringing the gap back to two.
Mid Northern's pack dominated the rest of the first half.
Their scrum was irresistible, pushing Kamo off their own ball with relative ease.
They mauled strongly off lineouts as well but for all their efforts, they couldn't cross the line.
Kamo scrambled bravely, holding out for as long as they could, but it was a matter of when, not if, Mid Northern would score.
Mid Northern were duly rewarded for their pressure when prop Chris Apoua crashed over right on half-time.
Halfback Malcolm McLeod converted the try, giving Mid Northern a 12-3 lead at the break.
Kamo looked to mount a challenge early in the second dig, putting early pressure on inside Mid Northern's half.
A penalty gave them the chance to reduce the gap to six, which Herman took.
Mid Northern then scored after a mistake from Herman.
Herman missed touch off a penalty and it sailed into hulking winger Wisea Lawabuca's hands.
From 55 metres out, Lawabuca ghosted through and scored an unconverted try in the corner to extend their lead to 11.
Ill-discipline began to plague the Kamo side, highlighted by a cynical play from lock Rueben Wright.
Lawabuca attempted a chip-and-chase, but was taken out late and high by Wright, who was consequently sin binned.
Losing a man in the pack made the Kamo scrum back-pedal even more.
Mid Northern took exploited the numbers advantage, scoring a try through flanker Tane Tale after spreading the ball wide.
Another long spell of no points filled the last quarter of the game with both teams scrambling on defence.
However Mid Northern ensured they had the final say of the contest with a last minute, long-range try from Lawabuca.
Lawabuca showed his speed once again as he raced 65 metres untouched to give Mid Northern the 27-6 victory.