Convicted double murderer John Barlow said fifteen years in prison was "like going into retirement" and hasn't changed him a bit, as he walked free today.

Barlow was released on parole from Rimutaka Prison in Upper Hutt this morning.

Pulling up at the family's modest Pukerua Bay home north of Wellington with wife Angela the 64-year-old said "it's a lot harder on the family left behind than it is the person who goes into prison".

"Obviously one would prefer to be at home but it's a bit like being retired early and you get a lot of reading done," he said. "It's not a holiday camp but prison is only meant to deprive a person of their freedom it's not meant to be any other form of punishment, it is of course for some people.

"I was nearly 50 when I went into prison and I'd led a fairly disciplined, organised life and travelled and educated so why would prison dramatically change me?"

Inside the car was a stack of cardboard boxes which the former antique collector said contained "reference books and paperwork", but declined to elaborate further.

Barlow had no words for the family of wealthy businessman Gene Thomas and his son Eugene, whom he was convicted in 1995 of killing in an execution-style shooting in offices near Parliament in 1994.

At his third trial Barlow was found to have shot the men with a restored gun from his collection, which was subsequently seized by police. He is never allowed to own firearms again.

"Not really there's nothing I can [say to the Thomases]... I'm not allowed to communicate in any way, directly or indirectly with them," Barlow said.

Nor would he delve into that evening in 1994, saying: "I don't want to canvas that".

Asked what next, Barlow said there were "a number of things we're looking at" to over-turn his conviction, but didn't "want to go into that now".

He wasn't fazed about what people thought or a public backlash to him being released.

"I don't think so I've been out in the community working around and being recognised over the last year or so."

Barlow was granted six home visits in preparation for his release from Rimutaka.

First thing on the agenda would be a cup of tea but beyond that he wasn't sure.

"It's a bit early for life plans," Barlow said, but later added that the section behind him would "keep him busy for awhile".

Barlow has always maintained his innocence - daughter Keryn has written a book on the subject - and did so again today.

"No I didn't [kill the Thomases], I didn't.. but I don't want to say anymore on that subject."

He was convicted of the double-murder in a rare third trial and sentenced to life in prison with a minimum non-parole period of 14 years.

The Parole Board denied his application last April finding he had "a completely inappropriate attitude to guns".

Barlow said the judicial system was designed so that the general public believed the verdict given.

"There's a huge resistance, not only in this country but in any country to people protesting their innocence and then when people are subsequetly found not guilty, well nothing much is said."

For the rest of today he planned to relax.

"I've got a lot of unpacking to do," Barlow said.