Opposition Leader Bill Shorten has called on Prime Minister Tony Abbott to fully explain to Australians a "bizarre" incident that prompted the Australian ambassador to France, Stephen Brady, to offer his resignation.

The federal government was in full damage control mode on Tuesday night, with Liberal Assistant Treasurer Josh Frydenberg asserting that he doubted the story was true and rushing to praise the ambassador's credentials.

Fairfax Media revealed on Tuesday that Mr Brady was on the airport tarmac in Paris with his partner of 32 years, Peter Stephens, waiting to meet Mr Abbott's incoming plane during a recent official visit to France.

The prime minister's travelling party sent an instruction that Mr Stephens should not take part in the greeting but should wait in the car. Mr Brady refused the instruction.

Mr Shorten said that "Australians deserve an explanation from Tony Abbott and if it's true, Ambassador Brady and his partner deserve an apology".

The Prime Minister's office has not denied the incident occurred.

Mr Frydenberg said he understood the Prime Minister had been "willing and wanting to meet them both" during an interview on the ABC's Radio National on Tuesday night.

"I doubt that [the story] would be true, because as I understand it the Prime Minister was very happy to meet the both of them. In fact the prime minister knows Stephen Brady very well, no doubt he has met his partner Peter before," he said.

Mr Frydenberg said he had been a good friends with Mr Brady for years and he was "a fantastic and loyal diplomat".

Mr Brady has had a long and distinguished diplomatic career in the public service and has has also served as official secretary to Dame Quentin Bryce and her successor, Sir Peter Cosgrove.

The Assistant Treasurer said he did not think it was "sinister" that the Prime Minister's office had not denied the story and suggested "there may be issues around protocol".

"I doubt the story is what people are trying to make it out to be because the prime minster would have a great deal of respect for Stephen Brady and no doubt would have been happy to meet his partner as I understand he was," he said.

This is not the first time that Mr Brady and Mr Stephens have come under the political microscope.

In September 2008, Liberal front bencher Michael Ronaldson claimed Mr Stephens was serving as the "chief operating officer for [Kevin] Rudd and [wife Therese] Rein Inc" during a Senate hearing.

Senator Ronaldson accused the former prime minister of using taxpayer money to fund Mr Stephens to be Ms Rein's personal adviser.

At the time, Labor angrily denied the claim and said Mr Stephens was employed in a range of roles in Mr Rudd's office.

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