An Air Force Orion aircraft has landed safely at Whenuapai Royal New Zealand Airforce Base after an incident which saw police poised to respond.

A New Zealand Defence Force spokesperson told the Herald the P-3K2 Orion undertook a precautionary shutdown of one engine, as the aircraft was leaking fluid.

"The aircraft landed safely back at RNZAF Base Auckland Whenuapai at 12.55pm today."

A police spokesperson told the Herald a small plane reported to be in difficulty on Monday afternoon, and emergency services were monitoring it, but it landed without difficulty.