Mr Brownlee said the Special Forces, which previously used different rifles to the Army, would also be using the LMT. He said this was a strong endorsement of the weapon. He added that the New Zealand Special Air Service (SAS) "liked what they saw".
The procurement comes 28 years after the NZDF was equipped with Austrian-made Steyr 5.56mm rifles, which many soldiers disliked and which had been criticised as unreliable and under-powered.
Mr Brownlee said the LMT was a "combat-proven rifle" that been used in "the most arduous conditions".
"It gives our personnel a weapon they can rely on in any situation," he said.
The minister said the new rifle was part of a package that included day and night vision scopes, a detachable grenade launcher, combat torches, laser sights, and sound suppressors.
"Our personnel operate by day and night in conditions ranging from the jungle, to deserts, to built-up areas," Mr Brownlee said.
"The new rifle has an open architecture that allows it to mount different sights and other equipment depending on the operational situation.
"It can be adjusted to fit the user and incorporates the latest technology in a light, simple and robust package."
The LMT weighed 3.3kg, which was slightly lighter than the Steyr rifle. The $59 million investment would cover the purchase of the weapons, support, simulation and training.
It was not yet known what the Defence Force would do with its 9000 Steyr rifles.