Wellsford are also coming into the playoffs with form.
Winning five of their last six games, the former champs will want to continue their rich vein of form.
An indifferent start put them in a precarious position, but they rallied to edge Otamatea out of the playoffs.
They'll be hoping for a reverse of fortunes when they face up with OBM as they were soundly beaten in both contests this season.
Meanwhile Mid Northern will take on Waipu in Hukerenui at the slightly later kick-off time of 2:45pm.
Mid Northern set the competition alight with a 12-game win streak from round three.
However, they were surprisingly defeated by Mid Western, which cost them first position.
While OBM have led the competition in points for and against, Mid Northern haven't been far off.
They've scored 820 points while conceding 17 points per game, both good enough for second overall.
Waipu, on the other hand, played very well for most of the season but a late lapse has seen them lose three of their last four games.
Waipu have also impressed on attack by scoring 30 points per contest.
However, they too will need to overturn Mid Northern's edge after twice losing to them during the round robin.
In other divisions, the grand finals have arrived for the Bay of Islands and Mangonui divisions.
Moerewa take on Kerikeri in the Bay of Islands final after winning their respective semifinals last week.
The final looms as a battle of the best, with both sides having extra motivation in beating each other.
They have lost only once this season, that being against each other.
Meanwhile Awanui will take on somewhat surprising finalists Te Rarawa in the Mangonui decider.
Te Rarawa beat second-placed Eastern in their semifinal, who had accrued three more wins during the regular season.
Awanui have been virtually unstoppable this seaon, only losing once and conceding just nine points per game.
