The State Solicitor's Office has asked a court to send construction unionist Joe McDonald to jail, or give him a suspended sentence, to discourage him from repeatedly breaking industrial law.
David Anderson told Perth Magistrate's Court yesterday that fines had failed to deter industrial breaches by McDonald, assistant secretary of the Construction, Forestry, Mining and Energy Union.
Mr Anderson said jail or a suspended sentence might be a suitable deterrent for McDonald, who yesterday pleaded guilty to trespass.
He said McDonald's history showed a blatant disregard for the law, with seven convictions for trespass and seven for remaining on site without lawful authority.
"It is quite clear that fines are not a significant deterrent, or indeed any deterrent," Mr Anderson said.
He told the court McDonald had trespassed on the John Holland children's hospital site in Nedlands on July 11 last year.
The court was told McDonald ignored a request to leave during his brief visit, during which he yelled at workers to attend a union meeting offsite.
Mr Anderson described it as a "blatant" and "calculated" breach of industrial law, claiming McDonald had "stubbornly refused" to leave.
McDonald faced a maximum penalty of a $12,000 fine or 12 months imprisonment.
Kevin Bonomelli, representing McDonald, said jail or a suspended sentence was not appropriate because McDonald had trespassed for less than a minute and had not disrupted work.
He said McDonald's last conviction for trespassing was two years ago, and at age 61 he was unlikely to reoffend before his retirement.
Magistrate Richard Bayly said he recognised some cases warranted consideration of previous offences, but he would base his decision on the incident before the court.
Mr Bayly said the matter did not warrant imprisonment or a suspended jail term.
However, he would impose a fine "with bite", issuing a $5000 penalty and a further $2230 in court costs.