"He is a high-risk offender and needs very careful rehabilitation and reintegration measures," the board said.
"It is clear that he is not able to manage or control his own behaviour, without robust oversight and supervision. His risk is described as high and he still offended in a manipulative way, despite intensive oversight."
He was convicted in 2009 for similar offending from 2006 and while serving his sentence breached his supervision conditions by accessing objectionable material on his computer.
After being jailed in 2014, Douglas was charged by police with possessing objectionable material relating to 11 images of prepubescent boys - most of whom were naked.
The board denied parole but his sentence ends on August 30, when he will have to be released from prison.
A parole assessment report stated Douglas' "lack of positive engagement and treatment to date in an obvious predilection towards serious sexual offending is of considerable concern as he is highly likely to access social media and pornography via the internet".
The board would assess him again in July in the hope of preparing him for reintegration and release.An extended supervision order - which allows Corrections to monitor and maintain the long-term risk of sex offenders and violent offenders - might form part of his release.
"He needs a strong, robust and carefully formulated release plan," the parole board said.
Douglas sexual offending began when he was a young teenager.
