SYDNEY - Prime Minister Kevin Rudd on Thursday urged Australian media not to "come the raw prawn" as he jokingly fended off howling criticism over his new blokey image.

Rudd reached again for his dictionary of working-class expressions after Australian commentators collectively cringed over his phrase, "fair shake of the sauce bottle, mate," which was delivered three times in one interview.

"I saw in this morning's press I was criticised for using some Australianisms," Rudd said at a book launch, before intentionally going into more of the same.

"And I'd just say too, well, I was having a Dad and Dave this morning - that's a shave - picked up my copy of the Oz (The Australian newspaper) and saw, was it George Megalogenis, having a go at me and I thought, 'fair crack of the whip.

"'Don't come the raw prawn with me, George."

"Or coming from Queensland I'd say, 'you'd get the rough end of the pineapple', but enough of that."

Rudd, once criticised as something of a policy wonk, this week also referred to Defence Minister John Faulkner as "Faulks" and claimed he had been "fair dinkum with the Australian people," underlining the linguistic transformation.

"Kevin, mate, hate to break this to you but this bloke bender you are on at the moment is not a good look," Megalogenis wrote in The Australian.

"The more you try to sound like a regular fella, the more you invite the punters to laugh at you."

Communication experts said the prime minister was deliberately trying to use down-to-earth language to connect with voters.

"He's doing it in ways that don't sound authentic and that's a big problem," commented opposition front-bencher Tony Abbot.