Members of the public are advised to avoid the Marne Road area, and officers have cordons in place for safety.
Hato Hone St John said crews were notified of the incident at 3.02pm.
“We responded two rapid response units, one ambulance and one manager to the scene.
A police officer stands guard outside a driveway leading to a block of housing properties on Marne Road in Papakura. Photo / Hayden Woodward
“Our crews assessed and treated one patient, who was transported to Middlemore Hospital in a serious condition.”
Photos from the scene showed police officers standing guard outside a house taped off on Marne Rd, while another officer stood next to a long driveway.
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