Can You Guess Which U.S. Ally Is Stockpiling $1.8 Billion Worth of U.S. Weapons? (Hint: It's Not Ira

China's first aircraft carrier, theLiaoning(PLAN CV-16), isn't nuclear. Its second carrier probably won't be, either. But what about the third... and the fourth? Source: Google Earth.

China is building a nuclear aircraft carrier, and it's making the neighbors nervous.

For months we've been hearing about Chinese military moves in the South China Sea -- everything from rattling Vietnamese fishing boats to cruising armed flotillas past neighboring islands, to building its own islands. In response, nations throughout southeast Asia and the Pacific are responding with military buildups of their own.

None more so than Australia.

Spoiler alert!That's right. The mysterious "U.S. ally" referenced above is none other than our friends from Down Under -- Australia.

In months past, we've talked about Australia's plans to potentially team up with Japan to build a fleet of diesel-electric submarines to keep watch on China from underwater, and its plans to buy MQ-4C Triton spy drones from Northrop Grumman , to monitor goings-on from the air.

Last week, however, produced evidence that Australia's military buildup is really kicking into high gear. In a pair of "notifications" to Congress, the U.S. Defense Security Cooperation Agency advised that Australia has requested authorization to buy $275 million worth of AEGIS missile defense software, hardware and other upgrades for its three new Hobart-class "Air Warfare Destroyers" from Lockheed Martin .

Artist's representation of Australia's new Hobart-class Air Warfare Destroyers. Note the kangaroo decal. Source: YouTube.

And that's not all. In addition to the destroyer upgrades, Australia has requested permission to hire Boeing to perform "sustainment" upgrades on three dozen of its most advanced warplanes -- two dozen F/A-18E/F Super Hornet combat jets, and one dozen AEA-18G "Growler" electronic warfare aircraft.

DSCA isn't specific on precisely what upgrades Australia is looking for the fighter jets, but they must be substantial. According to cost estimates from deagel.com, Australia could buy three dozen brand new F/A-18s for just $3.3 billion.

F-18s for Australia -- a new hope? Photo: U.S. Navy.

What it means to investorsYou take$275 million here, and $1.5 billion there, and pretty soon, Australia will be spending real money to beef up its military. And Australia's not alone.

According to naval analysts at AMI International, China's neighbors have plans to buy some $200 billion worth of submarines and surface combatants over the next 20 years -- making this regionthe world's second-biggest marketfor military warships. And take careful note: That's $200 billion for warships alone. It doesn't count spending on air forces (like Australia's F-18s) or even necessarily upgrades to existing fleets (such as the AEGIS systems for Australia's Hobarts).

This just goes to prove what I've already argued in the past: When investing in the defense industry, it's absolutely essential to keep an eye on which defense companies are winning market share in Southeast Asia and the Pacific. This week it's Lockheed Martin and Boeing taking home the lion's share of the loot from Australia's military buildup.

But what other major defense contractors are doing what they need to do, to expand their international businesses, and get more revenues from outside U.S. borders? Find out here.

And take an even more in-depth look at Australia's 10-year plan to beef up its military, right here.

Fighter jets and AEGIS ships are just part of Australia's military buildup. In 2011, Australia signed a multi-billion-dollar deal to acquire two dozen MH-60R "Seahawk Romeo" helicopters from Sikorsky. Source: Royal Australian Navy.

The article Can You Guess Which U.S. Ally Is Stockpiling $1.8 Billion Worth of U.S. Weapons? (Hint: It's Not Iraq) originally appeared on Fool.com.

Fool contributorRich Smithdoes not own shares of, nor is he short, any company named above. You can find him on CAPS, publicly pontificating under the handleTMFDitty, where he's currently ranked No. 327 out of more than 75,000 rated members.The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.