Bass Liberal MHR Andrew Nikolic has written to asylum seeker protest group Love Makes a Way spokesman Jeff McKinnon with an update on the number of children in detention and to spruik the federal government's immigration policy.

Eight members of the group - including Mr McKinnon - occupied Mr Nikolic's office earlier this month, demanding the immediate release of children in detention.

Mainland arms of the group took similar action in Geelong, which saw seven church leaders arrested.

Mr Nikolic said the number of children held in immigration detention had decreased further in recent months, and since the government was elected the number of children in immigration detention had decreased by 50 per cent.

"This inexorable decline is due entirely to the [Prime Minister Tony] Abbott government's border protection policies and our success in stopping the boats," Mr Nikolic said.

"Since the commencement of Operation Sovereign Borders, I am proud to say that there has been just one venture in the past nine months to make it to Australia," he said.

Latest figures show there are 603 children in detention.

Mr McKinnon said he had seen three different sets of figures, and called for greater transparency.

"When you're dealing with vulnerable people it's particularly important there's transparency," Mr McKinnon said.

"I think any children in detention is wrong, but I think it's great the government is decreasing the numbers.

"We want to know the government is willing to allow proper scrutiny of its figures."

Mr McKinnon said the group didn't have any further peaceful protests planned, but there was "rolling action" across the country.