The decision was announced by Australian Prime Minister Julia Gillard and Minister for Defense Stephen Smith and is contained in the 2013 Defense White Paper that details defense challenges and plans.
"Twelve Growler aircraft will enhance significantly the ADF's electronic warfare capability and, together with the (F-35) Joint Strike Fighter and the Super Hornet, will form a formidable air combat force capable of controlling both the air and electronic environments, the Defense Department said.
The procurement of the Growlers, made by Boeing of the United States, "is a prudent measure to assure Australia's air combat capability through the transition period to the (F-35) Joint Strike Fighter," which will come into service in Australia starting in 2020, it added.
The F-35s will replace the country's fleet of F/A-18F Super Hornet fighters.
The government also said it has decided its 24 F/A-18F Super Hornets in their current air combat and strike capability configuration instead of converting 12 of them to Growlers.
The Australian government approved the purchase of the first 14 JSF aircraft in 2009 but is so far contractually committed to two. Those two planes will be delivered in 2014-2015 for testing and training purposes.