Los Angeles (AFP) - For most Oscar nominees, the weeks before the February 22 ceremony are a whirlpool of stress.

But Laura Poitras, up for best documentary for "Citizenfour," insists it is like going for a healthy walk -- compared to what she went through to get here.

When former National Security Agency (NSA) consultant Edward Snowden, who revealed the massive scope of US intelligence surveillance, contacted the filmmaker, she found her life turned into a spy novel.

The most risky time was when she went to meet him in Hong Kong, with journalist Glenn Greenwald, the second person contacted by Snowden.

"I took some extreme precautions," she said, adding that she had a separate computer which she only consulted from public places.

"I didn't carry a cell phone for a year after I started reporting because I didn't want it to start broadcasting my location," she told AFP in an interview in Los Angeles.

It was this period that is recounted in "Citizenfour," a title which refers to the pseudonym Snowden used when he contacted her.

Poitras has already won a series of prizes for "Citizenfour," including a Bafta for best documentary. An Oscar, though, would "get more attention around this issue, surveillance," she said.

- Snowden helped boost 'awareness' -

She believes that Snowden's revelations, which won Pulitzer prizes for the Guardian and Washington Post journalists who reported them, helped to boost "awareness of what the government is doing to collect information... and the risk they are posing.

"People are using more encryption. Google is using more encryption of their servers. People are probably more careful with their information," she said.

Above all, the revelations have underlined that "intelligence agencies become out of control and are expanding at a faster pace than laws that regulate them," she said.

"Citizenfour," the third part of a trilogy about the US government's war on terrorism, was co-produced by Steven Soderbergh and edited by Frenchwoman Mathilde Bonnefoy.

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It notably shows Snowden explaining the so-called Prism US spy system, which monitors NSA data and communications, to Poitras, Greenwald and Guardian journalist Ewen MacAskill.

It also shows 31-year-old Snowden's paranoia about cameras and telephones. The hotel curtains are drawn; he gets stressed when there are noises. We also see him explaining his motivations, his anxiety about his girlfriend being harassed, guilt at having fled the US without telling her, and then later reuniting with her in Russia.

Snowden remains wanted by the United States, and lives in Moscow.

"The motivation for the film was really to tell the story of what happened, what was the motivation and why he took the risks that he took," Poitras said.

She says recognition for her film "probably provides a bit of shield for me in case the government would like to come after me in any form of legal way.

"It's a double-edged sword. People can contact me with projects who wouldn't have contacted me before, so it's higher profile. But most of the work I've done today I've been able to do it because I was actually kind of low-profile. So maybe now some people could think I'm too over the radar."