Mr Devanney said the new station would house one ambulance and there would be accommodation for staff wanting to volunteer who might live outside the area.
Mangawhai, like many coastal communities in Northland, was a place where the population swelled in summer and there was a real need for emergency services, he said.
"We still urgently need more St John ambulance volunteers in the Mangawhai area and we offer free training and qualification progression, not to mention their support of their community," Mr Devanney said.
He said the project would not have been possible without the Mangawhai St John Opportunity Shop, which raised funds solely for the purpose of contributing towards the building.
"Without the voluntary support of a dedicated op shop team and the support of the community using the Mangawhai St John op shop, none of this would have been possible."
More funding was needed to see the station reach completion, Mr Devanney said.