He thought it was struggling in the wind and described the conditions as overcast and breezy.
When he saw two fire engines rush past he thought, "Oh shit, I bet that helicopter's crashed."
The flight appeared to have come from Katikati, on the east coast, and had flown over Thompson's Track.
A police spokeswoman had no further details about the crash including the circumstances or whether it was a commercial flight.
Rooney said it appeared the road hadn't been closed.
St John tweeted they attended an "aviation incident" but nobody was taken to hospital.
Both people had minor injuries, the tweet said.
The Civil Aviation Authority said it hadn't received notification of the incident yet.
More to come.