Waitakere District Court was evacuated on Monday after an unknown white powder was found.
Three fire crews attended the scene, roping off an area inside the court building.
But almost two hours later, authorities confirmed the powder was a natural food grade product - more specifically, "a sugar-type substance".
Newshub understands the white powder fell onto the floor on level one of the building.
A Ministry of Justice spokesperson earlier told Newshub it was working with emergency services at the scene.
St John earlier attended the scene to keep an eye on six patients who had come into contact with the powder.