South West driving schools will become both instructors and assessors as part of a six-month trial that unions fear is the start of the State-wide privatisation of the sector.
The Transport Department has confirmed it will use external providers for heavy vehicle practical driver assessments in Bunbury and Busselton.
It said the operators would be subject to continuous stringent audits and monitoring to ensure their performance met the department's high standards.
But the Community and Public Sector Union/Civil Service Association said the trial should be shelved immediately or it would consider industrial action.
Branch secretary Toni Walkington said assessors feared the trial would be rolled out to other areas across WA.
She said it was another example of government privatising a service that should remain in the public hands and be free from any temptation of corruption.
"We call on the department to shelve any further privatisation trials and to listen to the major concerns of assessors," Ms Walkington said.
"Assessors want to have genuine consultation with senior staff within the next four weeks.
"If the department does not communicate with us properly, we will have a meeting to vote on possible industrial action."
A meeting of assessors in Perth earlier this month expressed concern at the credibility of the auditing of private companies.
"We can't understand why the Government would be handing over something like this to an unregulated industry," Ms Walkington said.
A spokeswoman for the department said there had been concern about the appropriateness of conducting heavy vehicle assessments within the Bunbury CBD, so tests were shifted to a light industrial area on the outskirts of the city.
But this arrangement has to end next month.To prevent a return of heavy vehicle assessments to the centre of the city, the department would trial the use of external providers for six months.
'The West Australian' is a trademark of West Australian Newspapers Limited 2013.
All rights reserved.
Select your state to see news for your area.