Manus centre has cost $2 billion: report

The detention centre on Papua New Guinea's Manus Island has reportedly cost Australian taxpayers around $2 billion since it reopened four years ago.

That's $1 million for each of the 2000 people who have been detained there, Fairfax Media reports.

Parliamentary Library analysts have trawled through years of Senate estimates hearing transcripts to piece together a total cost for the Manus Island operation.

They show the centre has cost Australians at least $420 million to build and maintain, and $1.25 billion to run since the Gillard government reopened it in late 2012, giving a total of more than $1.6 billion.

The library's figures do not include the last year of capital costs or the last four months of operating costs, estimated to add hundreds of millions more.

The figures also do not include the costs of resettlement, charter flights to and from the island, or the additional aid spending Australia has directed towards PNG in exchange for hosting the centre, much of that money lost to corruption, Fairfax reports.

Immigration Minister Peter Dutton confirmed last week that the centre, now holding 854 refugees and asylum seekers, would close after it was declared illegal by PNG's Supreme Court.