Peter Dutton has ripped into former prime minister Kevin Rudd over his approach to Pfizer executives.
Mr Rudd contacted the pharmaceutical giant to secure fast-tracked shipments of vaccines for Australia.
He then wrote Prime Minister Scott Morrison a letter to brief him on the discussions, with a deal announced eight days later.
"I suspect it wouldn't take our greatest detective within the Queensland Police Service to identify who leaked that self-serving letter," Mr Dutton told 4BC radio on Monday.
"Kevin claims credit for many things, it used to drive his Labor colleagues crazy."
The defence minister suggested Mr Rudd was inserting himself into the public debate because he was "bored to death in retirement".
"I wouldn't pay much attention to it," Mr Dutton said.
Mr Rudd met virtually with the global head of Pfizer on June 30 and asked whether the delivery of Australia's doses could be brought forward.
The pharmaceutical boss agreed to investigate what could be done.
On Friday, it emerged that more Pfizer doses would be delivered to Australia sooner than expected, with one million doses to be rolled out each week from mid-July.
The federal government confirmed it was aware of Mr Rudd's approach, but was not aware whether it had any impact on the outcome.
