By Lucinda Garbutt-Young

The coalition has “lost the plot” for calling for a police investigation into the reported leaking of a diplomatic note from Japan to Canberra over the prime minister’s “melons” comments, a Labor frontbencher says.

In an appearance on the Bush Deep podcast, which aired in July, the prime minister mentioned two crown melons gifted to him by his Japanese counterpart Sanae Takaichi.

When asked by host Nikki Osborne about how the melons were brought into Australia, Anthony Albanese said he didn’t know, while making hand gestures.

“She brought two, and they’re beautiful,” he said.

Media coverage over the comments in both countries prompted a letter from Tokyo to Canberra, which said there had been ”sensationalised reporting in the Australian media” about the interview, which was allegedly leaked to several outlets.

No action would be taken by the Japanese government over the incident, it reportedly said.

The comments largely escaped scrutiny when the podcast was published, but they were later picked up by Japanese papers, before Australian media ran coverage.

The coalition’s foreign affairs spokesman Ted O’Brien and his colleague, Senator James Paterson, this week wrote to Australian Federal Police commissioner Krissy Barrett and requested an investigation into how the leak occured.

”It is critically important that Australia’s bilateral partners believe that their confidential correspondence will be handled appropriately by the Australian government,” the letter said.

Mr O’Brien told reporters on Wednesday that “Japan is a special strategic partner of Australia and this has to be taken seriously. Trust is the currency of diplomacy.”

Housing Minister Clare O’Neil responded to news of coaltion’s probe calls by saying the Liberals had “absolutely lost the plot”.

“My personal view is that the Australian Federal Police should be allowed to focus on their job, which is keeping Australians safe and fighting crime for Australians,” she told Seven’s Sunrise.

Senator Paterson on Wednesday accused the government of having a “short memory”, given Labor Senator Katy Gallagher referred leaked correspondence between the then-coalition government and French Prime Minister Emmanuel Macron to the AFP several years ago.

“Labor can’t have it both ways. It’s either always wrong for confidential communications from our allies to find that their way into the media, or it’s wrong only when their political opponents do it,” he said.

The melons themselves, which AAP confirmed were valued at $400, fell under the expense threshold for reporting so were not recorded on the prime minister’s official gift log.

Senior government ministers including Tanya Plibersek, Senator Gallagher and Murray Watt have all defended the prime minister over the comments, though Treasurer Jim Chalmers declined to weigh in on so-called “melongate” when speaking on ABC Radio National.

“I take him (Mr Albanese) at his word when he says the way that it’s interpreted is not the way he intended,” he said.