Prison officers fear inmates will try to escape from WA's open prisons after 23 inmates were moved to higher security jails after a drug trafficker's escape during an outing in Perth's south.
Bernd Neumann, 59, escaped two weeks ago at Thomas Moore Park, Wilson, where he was walking a puppy being trained to help people with disabilities.
Police found no trace of him and are investigating whether he planned his breakout over 13 outings from Wooroloo Prison Farm.
In response to Neumann's escape, prison bosses have been reassessing all inmates with a minimum-security rating and approval to go on outings.
An internal directive, leaked to The Weekend West, reveals all jails have been ordered to ensure no inmate with more than five years to serve is rated as minimum security.
WA Prison Officers Union secretary John Welch said officers were concerned the Department of Corrective Services' response to Neumann's escape had the potential to destabilise prisons.
"These serious consequences could impact on the behaviour of prisoners in minimum-security facilities who perceive the changes to be having an impact on them," he said. Officers feared it was "raising the temperature" in minimum-security jails.
Mr Welch supported reassessing minimum-security prisoners in an "extremely delicate way".
Twenty-two prisoners have had approvals for outside activities revoked and were moved from farms into higher security.
Another prisoner, who did not have approval for outings, was also moved to higher security.
Neumann had only served three years of a 15-year term for a multimillion-dollar methylamphetamine conspiracy and would have been 71 on release if he had served his full term.
He was previously deemed a flight risk. When arrested in 2010 after skipping bail, he had official documents in another name.
Police are likely to check who visited or contacted him and whether he had help to get away.