MICHELLE DUFF

Spotted a bird, a plane or a UFO lately? Then the New Zealand Defence Force doesn't want to know about it.

The most recent installment of previously classified UFO files were made public yesterday – and within the documents, former chief of defence Jerry Mateparae makes it quite clear the military has no time for little green men.

"The NZDF does not have any expertise or role in respect of... `flying saucer' matters, nor is it qualified to address questions on the existence or otherwise of extraterrestrial life forms," he writes in a staff guide from October 2009.

"The NZDF believes that rational explanations, just as aircraft lights or natural phenomena, could be found for [unusual aerial sightings] if resources were diverted for this purpose but... it would be inappropriate use of defence resources."

All UFO reports should be referred to police, he said.

Meanwhile, a blue-tinted light racing across the North Island's night sky on Tuesday was definitely not a UFO. It has been identified by the Carter Observatory as an exploding meteor – one that could have been as big as a desk.

Witnesses were treated to a dramatic light shower after the meteor exploded 80km above Auckland. Some described the light as "several times brighter than daylight with a definite blue tint," and "like a firework," while a Raglan resident reported a sonic boom that "awoke the dog and nearby birds."

This was not an unusual occurrence, the observatory said, estimating it happened once every three years.

More than 2000 pages of Defence Force files, containing every UFO report since the early 1950s – including the 1978 Kaikoura lights mystery – were made public in December.

The most recent files, dating from 2009, contain news articles and Official Information Act requests from the public and media.

There is one reported sighting, of a wingless object appearing to have "magnetic media emitting from the ends," spotted flying over the Kapiti Coast last May. The Otaki witness informed the Defence Force he had submitted the photo to an expert analyst in the United States, and would keep it in the loop.

The files also show repeated requests by citizen investigators group UFOCUS for access to the Defence Force documents. In a 2009 letter, director Suzanne Hansen expresses her concern at the "marked increase" in UFO sightings around New Zealand.

Her organisation was receiving credible reports from farmers, hunters, logging contractors and scientists, which continued to "defy logical explanations” and fit with worldwide trends showing sightings were on the rise, she said.

Ms Hansen offered to meet the Defence Force to discuss UFO phenomena.

This offer went unacknowledged by Lieutenant General Mateparae when he replied to Ms Hansen a year later; assuring her the files were being declassified.

Before their release last year, he wrote to alert many of the agencies that had dealt with UFO sightings over the years – such as Internal Affairs, the Civil Aviation Authority, Metservice and Carter Observatory.

"While most correspondents were remarkably restrained in their comments (given a degree of skepticism about the subject)," he warned that some material could still "give rise to minor embarrassment."