Eleven protesters, including priests and pastors, have been removed by police from Foreign Minister Julie Bishop's office in Perth.

The group of Christian leaders was protesting about the 1,138 children being kept in detention centres on Nauru and Christmas Island.

They said they would not be silent until the government gives a release date for the child detainees.

While inside the office they conducted a prayer vigil around a photograph of Iranian asylum seeker Reza Barati, who who died in a riot on Manus Island in February.

Police said nine men and two women had been taken to the Perth Watch House and would be charged with trespass.

Police allege they refused to leave the premises when asked to do so.

Protesters outside the offices said those inside were happy to be arrested for the cause.

Protester Kris Kingwell said the group feels it is their role as Christians to speak for people who cannot.

"We're timing it because it's the beginning of holy week in the lead up to Easter," she said.

"As Christians we are responsible for loving and caring, for the care of those who can't care for themselves, and for advocating for those who don't have a voice of their own."

Reverend Chris Bedding kept repeating "1,138 children in immigration detention" as he was led to a waiting police van.