Vic prison release without parole doubles

The number of Victorian prisoners released without parole has more than doubled in a year and the ombudsman is worried offending behaviour has not been addressed before they leave jail.

Victorian Ombudsman Deborah Glass said more prisoners were serving full sentences and then entering the community without mentoring and reporting requirements.

This was due to parole reforms and some prisoners' inability or unwillingness to participate in necessary programs, she said in a discussion paper released on Wednesday.

"Prisoners who are not released on parole leave custody without the reporting requirements and controls that apply to parolees," Ms Glass said.

"There are legitimate concerns that some prisoners are being released without having addressed their offending behaviour."

Corrections Victoria data says 160 prisoners left prison on straight release in the 2012/13 financial year, which more than doubled to 365 in 2013/14.

Smart Justice spokeswoman Michelle McDonnell said the figures were concerning because there was strong evidence parole could help reduce the risk of reoffending.

"One of the consequences is that all those people are going to be released cold at the end of their sentence without any form of rehabilitation-focused supervision," she told AAP.

The ombudsman also found the growing number of prisoners was affecting access to rehabilitation programs and support, and she expressed concerns about the consistency and sufficiency of programs for indigenous and female prisoners.

Overall prisoner numbers are projected to increase by a further 1000 in eight months, with the state government and corrections implementing a building program to expand bed capacity.

Ms McDonnell said that added pressure meant there were even less prospects of people in the current system getting parole.

Ms Glass is investigating rehabilitation and reintegration of prisoners due to growth in inmate numbers, concerns about reoffending and the cost to taxpayers.