The group pleaded guilty to trespass after they were arrested and charged after participating in the nonviolent sit-in in Subiaco on April 14.
The peaceful protest was the latest in a series of sit-ins to highlight the treatment of more than 1100 children in Australia's immigration detention centres.
Pastor Jarrod McKenna, of the Westcity Church of Christ, is among those charged and also faced charges in Sydney after a similar incident at the office of Immigration Minister Scott Morrison in March.
In a statement, Pastor McKenna said activists had previously tried letters, submissions and sermons but were ignored.
“We believe we are called to dramatise this issue so it can no longer be ignored,” he said.
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He and ten others appeared in Perth Magistrate’s Court today, where no convictions were recorded. Fines were issued.
Pastor McKenna told SBS it was an incredible result, considering the potential jail time of 12 months.
"We are seeing leaders respond," he said.
"... More church leaders will be taking these actions until these people are free."
Before the hearings, supporters gathered outside the court.
The sit-ins - including those at the offices of Prime Minister Tony Abbott and Opposition Leader Bill Shorten - are part of the #LoveMakesAWay movement, whose leaders have been approached by Shadow Minister for Immigration Richard Marles since action began.
