As many as 350 Sidewinder tactical missiles may be sold to Australia under the U.S. Foreign Military Sales program.

The U.S. Defense Security Cooperation Agency, in its required notification to Congress, said the proposed sale carries a value of $534 million and that the U.S. State Department has given its approval for the deal.

"This proposed sale will improve the Royal Australian Air Force's air-to-air capability and ability to defend its nation and cooperate with allied air forces," the agency said.

The AIM-9X-2 Sidewinder is a short-range air-to-air weapon. The original weapon was developed in the late-1950s.

In addition to the missiles, Australia has also requested AIM-9X special air training missiles, captive air training missiles, missile tactical guidance units, containers, test sets and support equipment.

Spare and repair parts, personnel training and training equipment, and logistics and program support are also part of the package which requires congressional approval.

The principal contractor for the deal would be Raytheon Missile Systems. If the sale is approved, some assignment of U.S. government or contractor representatives to Australia may be required to provide technical and logistics support.