The WA opposition leader has conceded the Liberal party made a mistake in government with its handling of the run-down Broome Regional Prison, which has been found to be inhumane and unfit for purpose.
Inspector of Custodial Services Neil Morgan said in a report on Tuesday that conditions in the male maximum-security unit were degrading and the worst in the state, with overcrowding, poor hygiene, no personal space and potential contact with vermin.
Mr Morgan described the prison as "old, decrepit and crowded" and "not fit for purpose as a modern prison."
He likened the conditions in the men's maximum security unit as "the worst in the state".
"The conditions in the maximum-security unit were inhumane and degrading."
Opposition Leader Mike Nahan said yesterday it was a mistake for the former government to announce the prison would close by December 2015 following years of neglect, then backtrack without firming plans for its future.
He said the prison was in need of substantial upgrades, but added that when the previous Barnett government came into power in 2008 there was a backlog and they invested more than $1 billion in prisons overall.
WA Prison Officers' Union secretary John Welch said the findings of the report, including that there had been years of poor planning and a lack of investment, were expected and the union had been raising concerns for years.
"The low staffing levels coupled with the lack of work, education and programs for prisoners, has created a dangerous working environment for our prison officers," he said.
"We also share the inspector's concerns about the lack of appropriate cultural training and culturally appropriate services, given the very high proportion of Aboriginal prisoners incarcerated at the prison."
The prison manages male and female inmates of all security levels from across the Kimberley region, and is the oldest prison in WA.
Mr Welch said while the Labor government's recent $2.7 million funding commitment to upgrade the prison was welcomed, a long-term plan for the custodial needs of the region was urgently needed.