The Australian Government has appealed to the United States for help in gathering all the personal communications of Australians that it can.

Security officials wanted to cast a blanket of surveillance over the entire nation out of fears that Australians are involved in international extremist activities, and looked to the United States' National Security Agency (NSA) for help.

Those are the claims made by Glenn Greenwald - one of three journalists to whom whistleblower Edward Snowden gave masses of secret intelligence documents, and the author of a new book on the leaks.

The book includes an email from the acting deputy director of the Defence Signals Directorate (DSD) in Canberra, asking for an enhanced of the partnership between the two spy agencies.

“They wanted to have the NSA observe Australians more aggressively than ever before, and were making the case as to why the NSA should do that,” Mr Greenwald told reporters this week.

He says that while there is plenty of legitimate state surveillance going on, this request is dangerously broad.

“The problem is, and if you look at the letter ... they're not asking for very specific individuals to be surveilled. They're asking for a wide surveillance net to be cast over the Australian communications system,” Greenwald said.

Speaking to the ABC ahead of his book launch in Australia, Mr Greenwald said the incredible power of modern spy agencies must be kept under control.

“Historically, whenever you allow government officials to engage in mass surveillance... the abuse is virtually inevitable,” he said.

“I think it would be a much different story if the letter [was] saying; ‘Here are 35 people we're concerned about and we'd like you to help us watch them’, but that's not what the letter was.

“It was asking for, more or less, indiscriminate surveillance on Australians.”

He says the scale and boldness of digital surveillance has been a major revelation from the Edward Snowden leaks.

“Ultimately what I really believe is the most enduring and consequential revelation is that the goal of the NSA and its four English-speaking partners, which includes Australia, the UK, New Zealand and Canada, is captured by this phrase that appears over and over in the documents, which is ‘Collect it all’.”

“What we told people who didn't already know were ordinary human beings around the world, by the hundreds of millions, that the target of the surveillance system is not Osama bin Laden and his compatriots overwhelmingly.

“It is instead them, people who are guilty of absolutely no wrongdoing,” he said.

“They literally want to store and gather and ... monitor and analyse all forms of human communication that take place electronically.

“If the Government is going to do something that profoundly significant, we ought to know about it and be able to debate it.”

There has been widespread condemnation of Mr Snowden’s leaks and the subsequent reporting on their content.

The most recent Australian opposition came from recently retired General Keith Alexander, who last week told the Australian Financial Review that the whistleblower endangered people's lives.

Mr Greenwald disagrees.

“I think the critical thing to note is that people who wield power in every country generally dislike transparency,” he said.

“If you look at the history of the United States over the past 50 years ... in every single case where somebody has come forward and disclosed information that the government want hidden ... the US government says: ‘You're endangering lives, you have blood on your hands, you're going to cause people to die’.

“It turns out to be completely untrue ... it's a fear-mongering technique designed to discredit basic journalism and transparency, and that's absolutely the case here.”

“There's zero evidence that anybody has been harmed in any way by Edward Snowden's revelations, other than the political leaders whose reputations and credibility have suffered.”

Mr Greenwald also slammed the former General’s claim that the leaks inform terrorists as to the capability of spy agencies, calling it “absurd”. He says terrorists are already one step ahead.

“Terrorists have known forever that the US government and its allies are doing everything they can possibly do to learn the contents of their communication,” he said.

“That's why Osama bin Laden would only communicate by human courier, because he knew that electronic means of communication were compromised.”

The book is called No Place To Hide.