Defence is preparing to dump a trouble-prone fleet of armed choppers with more reliable American aircraft.
The army's Tiger armed reconnaissance helicopters have been plagued by design flaws and reliability issues.
Defence Minister Linda Reynolds has approved the purchase of 29 Apache Guardians to replace the choppers from 2025.
"The Apache Guardian is the most lethal, most survivable and lowest risk option, meeting all of Defence's capability, through-life support, security, and certification requirements," she said on Friday.
"By pursuing a proven and low-risk system offered by the Apache, Defence will avoid the ongoing cost and schedule risk typically associated with developmental platforms."
Senator Reynolds said Defence had learnt lessons from the European-designed ARH Tigers and opted for "proven and mature" replacements from Boeing.
Australian Associated Press