A minimum security prison in WA could be interrupted by industrial action, with workers voting to amp up their arguments amid stalled pay negotiations.

Staff at Perth’s Wandoo minimum security prison want a 3.75 per cent pay rise over three years, but their employer (Serco) has only offered 3 per cent.

The workers are represented by the WA Prison Officers' Union, whose secretary John Welch says staff only want a pay increase to match the amount Serco has offered workers at the other WA prison it runs, Acacia.

“Staff at Acacia were granted a pay rise of 4.25 per cent annually last year and Wandoo staff don't understand why their offer is so much lower,” he told the ABC.

“They want similar conditions ... we think that's a fair expectation of the one employer.”

Staff will talk about a range of actions at meetings this week, from refusing to take phone calls to work stoppages.

“Our members will be taking action with a heavy heart,” he said.

“They had hoped the employer would value them enough to come to the table with reasonable offers to resolved this.

“They'll be very disappointed if Serco does not come back to the table and sit and negotiate a settlement.

“The role of the prison officer, the role of the administrative staff who would be involved in this industrial action would have a very significant impact if they were to withdraw their labour.”

Serco has told reporters that it offered a pay increase of nearly double the current CPI, which was higher even than Fire and Emergency Services and WA Police.

The company says it offered to introduce paid parental leave and a range of allowances as well

The union will hold meetings this week to discuss when and in what form it will take action.