David Eastman's conviction for the high-profile murder of police chief Colin Winchester on January 10, 1989, was quashed in 2014 and a retrial ordered after a judicial inquiry found the conviction was based on flawed forensic evidence and he had suffered a miscarriage of justice.

The assistant commissioner was shot in the head at close range as he got out of his car at his home in Deakin.

A jury in November last year acquitted Mr Eastman of the murder.

Mr Eastman, 74, is suing the ACT government for wrongful imprisonment under the territory's Human Rights Act, and the case opened in the ACT Supreme Court on Tuesday.

"I suppose you could say incarcerated economist," Mr Eastman told the court when among the first questions asked of him was what his occupation had been for the past 25 years.

On his release on bail in 2014 following his conviction being quashed, Mr Eastman said he had been picked up by volunteers from St Vincent de Paul, who had arranged civilian clothes from Target for him that allowed him the gratifying experience of being able to shed his prison greens for the first time in 20 years.

The volunteers had arranged the age pension for him as well.

Mr Eastman said they drove straight to Sydney for a break.

They stopped at McDonald's on the way. "It was a beautiful atmosphere," he said. "You wouldn't think that a McDonald's would be anything extraordinary but it was a safe and friendly atmosphere."

They went to Penrith Panthers Leagues Club in Western Sydney where there was a huge crowd, and Mr Eastman said concerns he had held that he would be fearful left him.

"I guess I was getting something of which I'd been starved," he said.

There were people of all ages, laughing and enjoying themselves, and he was not worried about his physical safety.

"Jail's a dangerous place. You have to be on the watch all the time."

He spoke of feelings of elation on his release and being in a "euphoric state", deriving pleasure from doing ordinary things.

He was able to visit the graves of his mother and twin sisters in Sydney.

Mr Eastman, who wore his right arm in a sling after tripping on a footpath, told the court they then drove to Melbourne and stopped at Wilsons Promontory National Park.

He was not confident about swimming in the surf. He said he became aware on his release from jail of how much he had aged and how he was not as fit as he once was.

When he returned to Canberra a teenage girl offered him a seat on the bus and he thought she was joking.

He said he realised that was how the world now saw him, and the implications that would have in his search for employment.

Mr Eastman said he would always remember the wonderful moment the jury unanimously found him not guilty.

There was a bittersweet feeling of freedom with a sense of loss, he said.

"I was free to get on with my life, but realistically I'm free to get on with what's left of my life."

He said his time in jail had cost him the opportunity to get married and have children and a career.

The court also heard that ACT Treasurer Andrew Barr had offered Mr Eastman an act of grace payment on condition he sign away his legal rights and discontinue his suit against the government.

But Mr Eastman rejected the offer. Lawyers for the former Treasury official told the court there was a complete lack of transparency about how the amount had been calculated.

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Mr Eastman's silk, Lisa De Ferrari SC, said he wanted nothing more than the court to recognise his rights to compensation and award compensation at an amount the court determined.

"What he doesn't want is to be fobbed off by the Crown," she said, for an amount determined by the Treasurer, "if you give up your rights".

Outside court, Mr Eastman's solicitor Sam Tierney said the result would be a landmark decision.

"There is no equivalent statute that's been tested in Australia so we're breaking new ground," he said.

"But certainly we are of the view that the words in the sections of the Human Rights Act are pretty clear."

The trial, before Justice Michael Elkaim, continues.