The Defence Force is battling a blaze in bushland at the Waiouru Military Camp in the central North Island, which started during a live fire exercise yesterday.
It is the second fire to have been sparked during military exercise yesterday, the other on an Army base near Christchurch.
Both are under investigation.
A Defence Force spokesman said the Waiouru blaze had burnt through about 350ha but was now contained in a 5ha gully of dense vegetation in the Three Kings area.
Five civilian helicopters and a Royal New Zealand Air Force helicopter are fighting the blaze, which started during an exercise by the Singaporean Armed Forces.
