Customs are investigating Hamilton company Pacific Aerospace for allegedly exporting parts to North Korea.
A New Zealand-made aircraft from Pacific Aerospace turned up at a North Korean military airshow painted up in the hermit state's colours in September last year.
The plane was photographed at North Korea's first ever public airshow, which featured fighter jets and military helicopters. The Hamilton-made PAC P-750 XSTOL, which has a North Korean flag on its tail, is used for skydiving and could be used by paratroopers.
Pacific Aerospace chief executive Damian Camp said at the time he was looking for answers.
"We're trying to get some detail on that because that aircraft is owned and operated by a Chinese company."