A veteran spy watcher claims Australia is playing a role in America's intelligence networks by monitoring vast swathes of the Asia Pacific region and feeding information to the US.

Key points: Spy expert Des Ball says Australia has been monitoring the Asia Pacific region for the US

Spy expert Des Ball says Australia has been monitoring the Asia Pacific region for the US He says Australia has four key facilities that are part of the NSA's XKeyscore program

He says Australia has four key facilities that are part of the NSA's XKeyscore program Senator Nick Xenophon says the Government must ensure Australians are not under US surveillance

Senator Nick Xenophon says the Government must ensure Australians are not under US surveillance Meanwhile, former NSA executive Thomas Drake has lifted the lid on spy practices

Intelligence expert Professor Des Ball says the Australian Signals Directorate - formerly known as the Defence Signals Directorate - is sharing information with the National Security Agency (NSA).

The NSA is the agency at the heart of whistleblower Edward Snowden's leaks, and has recently been accused of tapping into millions of phone calls of ordinary citizens in France, Germany and Spain.

Mr Ball says Australia has been monitoring the Asia Pacific region for the US using local listening posts.

"You can't get into the information circuits and play information warfare successfully unless you're into the communications of the higher commands in [the] various countries in our neighbourhood," he told Lateline.

Mr Ball says Australia has four key facilities that are part of the XKeyscore program, the NSA's controversial computer system that searches and analyses vast amounts of internet data.

They include the jointly-run Pine Gap base near Alice Springs, a satellite station outside Geraldton in Western Australia, a facility at Shoal Bay, near Darwin, and a new centre in Canberra.

Spies grilled over NSA operations

The United States' top intelligence chiefs have fronted a congressional hearing over the NSA's spying operations. Director of the NSA general Keith Alexander told the hearing that reports the US collected tens of millions of phone calls across Europe were "completely false". Meanwhile, the US director of national intelligence, James Clapper, said US agencies do not spy on Americans, nor do they "indiscriminately" spy on the citizens of any country. Mr Clapper said spying on foreign leaders are nothing new. "It's one of the first things I learned in intel school in 1963: that this is a fundamental given in the intelligence business," he said. Read more.

Mr Ball says security is the focus for Australia's intelligence agencies.

"At the top of [the list of priorities] you're going to find communications relating to terrorist activities, particularly if there's alerts about particular incidents," Mr Ball said.

A secret map released by Snowden revealed the US had also set up surveillance facilities in embassies and consulates, including in Jakarta, Kuala Lumpur, Phnom Penh, Bangkok, Yangon, Manila, Hong Kong, Taipei, Shanghai and Beijing.

"Australia itself has used foreign embassies for listening purposes [in] an operation codenamed Reprieve ... in which we've used embassies in our region to monitor local, essentially microwave-relayed telephone conversations," Mr Ball said.

"The fact that the United States has special collection elements that are doing this today is no different from what many other countries are doing today. It's not unusual."

Some critics have raised concerns about the extent of the NSA's spying program, suggesting that communications of ordinary Australians may have been pried on.

Xenophon calls on Government to protect Australians from US surveillance

Mr Ball says Australia, the US, the UK, New Zealand and Canada have a long-standing "five eyes" agreement to not spy on each other, and he believes it has not been breached.

"The fact that it hasn't [been breached] for over five decades I think signifies to the integrity of at least that part of the arrangement," he said.

But independent Senator Nick Xenophon says the Government should do more to ensure Australians are not subject to the surveillence from US agencies.

"At the very least, the Australian Government should be calling in the US ambassador and asking whether the level of scrutiny, the level of access to citizens' phone records in Germany, France and Spain, has been happening here," he said.

"I think we deserve an answer on that."

Former NSA executive lifts lid on spy practices

In 2010, former NSA senior executive Thomas Drake was charged with leaking government secrets to a journalist.

He was tried under the US espionage act but his case was ultimately reduced to a minor misdemeanour charge. He escaped a jail sentence after a finding that the information he disclosed was not classified.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 15 minutes 15 seconds 15 m Thomas Drake joins Lateline

He agrees with Mr Ball that the US has not breached its spying agreement with Australia.

But he told Lateline those five nations do "utilise each other's services" to gather information on other "fair game" nations.

"Much of it is legit, but increasingly since 9/11 because of the sheer power of technology and access to the world's communication systems ... [agencies have] extraordinary access to even more data on just about anything and anybody," he told Lateline.

"And what they want is to do so and have access to it any time, anywhere, any place."

US moves to ease concerns about NSA

US president Barack Obama has come under fierce criticism over allegations that the NSA tapped the mobile phone of German chancellor Angela Merkel and conducted widespread electronic snooping in France, Italy, Spain and elsewhere.

Amid a growing uproar, White House officials have said they will review intelligence collection programs with an eye to narrowing their scope.

"We need to make sure that we're collecting intelligence in a way that advances our security needs and that we don't just do it because we can," White House spokesman Jay Carney said.

Sorry, this video has expired White House sees need for 'constraints' on NSA spying ( North America correspondent Lisa Millar )

Mr Drake says it is alarming that a nation would spy on those it considers allies.

"Spying on others is considered the world's second oldest profession and so the idea that nation states would engage in spying on others is no surprise, not at all," he said.

"I think what's particularly pernicious here is the fact we're actually listening on the personal communications of the highest levels of governments in countries that are supposed to be our allies and are actually partnered with us in ensuring that we deal and defend against threats to international order and stability."

Spying 'done behind the veil of secrecy'

He says most countries go along with US requests for data.

"It's heavy stuff and when it's done behind the veil of secrecy, outside the public view then hey, it's whatever you can get away with because you can," he said.

"Just because you can doesn't mean you should and I actually think it's encouraging the countries are standing up against the US in this regard because it is overreach.

"It really is going far beyond the mandate to ensure international order and stability, even in partnership with other countries.

"The real fundamental threat here though is ultimately the sovereignty of individuals, who we are as people. We're supposed to have rights.

"What's happened after 9/11 is now security has kind of taken primacy over rights and liberties because of the real or perceived threat."

Snowden 'aware his revelations have been explosive'

Snowden is currently holed up in Russia after leaking information about America's vast surveillance operations.

Mr Drake recently met Snowden in Moscow, and says the former NSA contractor is aware his disclosures have been "quite explosive".

"His focus is on reform. His focus is on rolling back the surveillance data. His focus is repealing many of the enabling act legislation that put all this into place, or at least enabled the government in secrecy to expand the surveillance date far beyond its original mandate," Mr Drake said.

"He's obviously grateful that he's got temporary asylum in Russia. I don't think it was certainly not a place he was planning on going to or remaining in for any length of time.

"He's looking forward, at some point in the future, to returning to the US but that's certainly not possible right now.

"The US has already levied serious charges against him including the same charges that they levied against me under the espionage act."