The Armed Offender Squad have been called to a rural property north of Dargaville.
Sergeant Darren Sullivan said there had been a serious assault in the early hours of this morning and as a result police were searching for a man.
It was believed a small contingent of armed police went to the property about midday after reports he was holed up in a house.
More members of the squad were called for about 3.35pm.
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