When journalist Anne Summers was a 21-year-old student in Adelaide in the 1960s, she had no idea her movements, contacts and phone conversations were under surveillance by ASIO.

It was not until she obtained her file three years ago that she discovered she was among many Australians who were followed by government spies for decades.

"I was shocked and my overwhelming sensation was the file confirmed the paranoia we had as students in Adelaide, marching down Rundle Mall chanting about war, convinced we were being followed and photographed," she told a forum about the book Dirty Secrets at the Sydney Writers' Festival (SWF).

Former High Court judge Michael Kirby had a similar story.

As a student at Sydney University he was also involved in student politics, and when he obtained his ASIO file, he discovered he too had been under surveillance.

"We do need a security service, but we've got to keep a foot on the ground," he said.

Summers and Kirby are among 27 contributors to the book with revelations about early days as liberal-minded, anti-conservative activists.

Others include former Tasmanian premier Jim Bacon, gardener Peter Cundall, Aboriginal activist Gary Foley, gay rights activist Lex Watson and former MP Meredith Burgmann, who edited the book and chaired the SWF forum.

Her sister, Verity Burgmann, was another who was spied on, including her participation in the Canberra Trotsky Society, that had a handful of members.

Meredith Burgmann signs a copy of Dirty Secrets at the Sydney Writers' Festival. ( ABC: Anne Maria Nicholson )

"There were 10 photos of her in the file, all of them standing on a beach in a bikini," Ms Burgmann said.

But Ms Burgmann said there was a shocking aspect to the files, and they had impacts on the lives of people who knew they had been followed and reported on by people they trusted.

Elizabeth Evatt, former chief judge of the Family Court of Australia, and daughter of NSW Labor MP Clive Evatt, told the forum her father was "seen as dangerous" by ASIO because he was a dissident.

She said his file showed he had been monitored because of his public stands on freedom of expression, Aboriginal land rights, conditions of migrants and even authorising a Sunday dance as chief justice when it was not lawful.

She said the darker side of the surveillance was that he was followed because he supported international causes that the government of the day disagreed with, including the independence movement in Cyprus.

"People who dissented or disagreed with the government got ASIO files," she said.

"None of them were involved with trying to overthrow the government or were suspected of being involved with violent overthrow."

Summers said she found it "creepy" to read that ASIO was monitoring all her movements, including a flight from Adelaide to Sydney.

She said ASIO was unaware Sydney was her hometown and she was returning home.

She revealed her own father was an ASIO spy, "watching visiting Russian ships and noting down all the number plates of cars going to meet them", and this link was not picked up.

Her file made a telling conclusion: "Capacity for Violence: Nil."