The review also reveals that the immigration minister Peter Dutton was routinely given a heads up by the department prior to the release of documents to journalists and members of parliament.



“Based on the information before me, I find that the department's failure to meet the statutory processing time for processing 'significant/sensitive' and non-personal FOI requests is systemic,” Pilgrim wrote.

“It is also apparent that in the majority of cases, the delay has been caused by internal factors, particularly the internal consultation process.”

Shadow immigration minister Shayne Neumann said: “This investigation has exposed the Department of Immigration and Border Protection’s culture of secrecy and its failure to meet the statutory processing times for Freedom of Information requests.

“I know first-hand the department’s systemic failure to meet statutory timeframes and process FOI requests within 30 days. I submitted a simple FOI request to the department in October 2016 and only received a decision this month — 426 days after my initial request.”

Neumann also said the immigration minister needed to explain “whether he or his staff members have ever asked the department to go slow on FOI decisions or asked for certain information to be withheld.”

Australian Greens senator Nick McKim said there was “no reason at all for journalists’ FOI requests to be handled under a separate process, nor should they be subject to political interference and meddling”.

He said that “the buck of course stops with Peter Dutton”.

“He will do whatever it takes to keep secret the horrors of offshore detention, including repeated breaches of freedom of Information laws,” McKim said.

Dutton has not responded to requests for comment about the review, or his office’s involvement with journalists’ FOI requests.

Senior immigration department officials had previously denied there was any “freeze” on processing requests about Nauru.

In Senate Estimates this year department secretary Michael Pezzullo and assistant secretary Ben Wright were questioned about the internal delays. Wright told parliament: "We process all our FOI requests as per the FOI legislation and definitely there is no freeze on FOI requests."