Auckland Central Remand Prison at Mt Eden is being signed over to private management.
The prison was taken out of private hands in 2005 by the then-Labour Government.
Late last year multinational firm Serco won a $400 million contract to run the jail for at least the next six years.
The Government says it expects the private operator to deliver cost savings as well as innovation.
Once the contract is signed at the prison on Tuesday, a phased handover will begin and be completed by August.
The details of Serco's contract have been kept under wraps are due to be tabled in Parliament within a fortnight.