In one week the US has arrested 10 alleged Russian spies and Canada's top spy has said ministers in two provinces are ''under the influence of a foreign government'', assumed to be China.

The world is suddenly being re-introduced to the shadowy world of state-sponsored espionage.

The methods used by the spies and described in an FBI affidavit sound like something out of Burn After Reading, the Coen brothers' 2008 spy spoof.

The 37-page document shows that Moscow Centre may have added internet technology to its bag of tricks but its main revelation is that Russian intelligence evidently still relies on espionage methods - "tradecraft" in spy lingo - as old as the Rome hills.

According to the FBI, the suspected Russian agents it rounded up sometimes communicated with Moscow via secret messages hidden in web pages (in a process called steganography).

But for the most part, they contacted each other the old-fashioned way, through furtive exchanges in city parks, bags of cash hidden along country roads, even by radio with Morse code.

"The FBI's investigation has revealed that a network of illegals … is now living and operating in the United States in the service of one primary, long-term goal," the affidavit read, "to become sufficiently 'Americanised' such that they can gather information about the United States for Russia."

The FBI's spy-busting techniques were quaint as well. Agents put "microphone-type listening devices'' in the homes of the alleged spies. They "surreptitiously entered certain of the defendants' residences; photographed evidence and copied electronic media while inside''.

But the FBI may never find out who the alleged spies really are, because of another tried and true technique Moscow Centre uses, according to the affidavit: obtaining the birth certificates of dead Canadians and Americans, with which they can build a whole new, false "legend" for their spies.

The affidavit turns up several.

That old trick could well prevent the FBI from ever finding out who all these people really are.

Could such a thing occur in Australia?

''Can you imagine that we're in such a virginal state that it doesn't happen here? Of course they are [here],'' says Warren Duncan, a former Australian Secret Intelligence Service officer.

While Australia may not be as rich a target as the US, there are billions of dollars to be made via infiltration of our industries and important secrets to be gleaned from our state apparatus.

No one in government would comment about the possibility of foreign agents in Australia, though it was only a month ago that the Australian government ejected a member of the Israeli embassy in Canberra.

The arrests of the alleged Russian spies showed that the tradition of espionage did not disappear with the Berlin Wall.

Agents and their subterranean world of coded messages, invisible ink and early morning package drops just vanished from the public interest. Spies are an accepted, if rarely mentioned, part of international relations and they exist in most countries.

There are spies within diplomatic missions, on university campuses, in the private sector and among the public service. Even in Australia.

Dylan Welch with The Washington Post