The Prime Minister doubts whether the hunt for the Ministry of Foreign Affairs leak will find the culprit.
The State Services Commission is investigating how a cabinet paper outlining revised restructuring plans, made it into the hands of Labour MP Phil Goff.
John Key supports the inquiry but is pessimistic over the outcome.
"I've been very historically sceptical. There's been, in the time I've been Prime Minister, a number of investigations in this regard, and I've never found a successful answer yet."
Photo: John Key (Getty Images)