The decision said Wilson had refused to take part in the preparation of a parole assessment report, refusing to provide any information about his release proposals other than that he was working with the prisoners aid and rehabilitation trust to find accommodation.
He also refused to indicate in what part of the country he intended to reside.
"The report also referred to Mr Wilson's continued denial of responsibility for his offending and his refusal to engage in any programmes which could assist him in addressing his offending and assisting with his reintegration,'' the decision said.
"The tenor of the report makes it clear that Mr Wilson has been positively obstructive of efforts to help him and that this has been his attitude throughout.''
The board said Wilson remained a risk to society because of his ability to avoid detection, his complete denial of responsibility for his offending and his unwillingness to participate in any treatment programmes.
A report prepared for the board by a clinical psychologist identified no information that could lead to a change of previous assessments of Wilson as posing a high risk of sexual recidivism.
"She did note nevertheless that recent interactions may indicate a greater willingness from Mr Wilson to engage with departmental staff,'' the decision said.
In the board's view, "the personal factors uniquely applying to this offender point to the strong likelihood of further similar sexually deviant behaviour occurring as soon as he has the opportunity to engage in it''.
A Parole Board spokeswoman said the board had been clear about the danger Wilson posed for many years.
However, it was restrained by legislation and could not keep him in prison past his release date on September 1, she said.
The Government plans to introduce legislation to Parliament allowing the board to keep prisoners in jail indefinitely if they believe they pose a high risk of imminent and serious sexual or violent reoffending.
But the bill is not expected to be passed by September 1 and will not be used on Wilson because it won't apply retrospectively.
Justice Minister Judith Collins said one of National's campaign promises was to introduce a civil detention regime that would allow the High Court to order individuals be held in custody until the Parole Board was convinced they were safe for release.
"I am pleased to say that legislation for public protection orders is currently under development as a standalone bill, and will be introduced to the House as soon as possible this year. Once the legislation is introduced to the House, we will have a clearer idea of the time it will take to pass.''
She said public protection order legislation was not being designed to target a specific individual.
The new orders are expected to apply to between five and 12 offenders over a 10-year period.
"The majority of these people are expected to be child sex offenders.''
The draft legislation would be assessed for consistency with the human rights affirmed in the New Zealand Bill of Rights Act 1990.
