Ex-Aus PM reignites Trump tit for tat despite trade worries

Malcolm Turnbull has made his third anti-Donald Trump foray in 24-hours to press his argument about the president's character, as Australia tries to clinch an exemption from US trade tariffs.

The ex-Liberal prime minister isn't backing down and insists Australians shouldn't be scared of offending Trump's "huge ego", despite suggestions his criticism could jeopardise negotiations.

"Surely we should be free to speak the truth," he told ABC radio on Tuesday.

"Or are we going to muzzle ourselves for fear of offending Mr Trump?

"What every nation needs to do is to stand up to him, because otherwise it's a slippery slope."

Trump criticised the former politician, who negotiated an exemption during the president's first term, just days before America's 25% tariffs on steel and aluminium imports are due to take effect.

The spray happened on the social media platform Truth Social, which is owned by Trump Media, on Monday afternoon (AEDT) after Turnbull gave a critical interview to the Bloomberg news service branding the president as rude, erratic and playing into China's hands.

"Malcolm Turnbull, the former Prime Minister of Australia who was always leading that wonderful country from "behind", never understood what was going on in China, nor did he have the capacity to do so," the president wrote.

"I always thought he was a weak and ineffective leader and, obviously, Australian's (sic) agreed with me!!!"

Turnbull lost the prime ministership in a party leadership spill and was not voted out by the public.

Turnbull returned fire on Monday night, telling ABC TV Australia had to be realistic about the impact Trump was having and warning China would take advantage of his "erratic" behaviour.

On Tuesday morning, he re-iterated and added to his comments about the president on ABC radio.

"He's a bully, he seeks to achieve dominance and he gets dominance by intimidating people," Turnbull said.

"I talk about these issues and write about them all the time, so I've got no idea why Donald Trump suddenly decided to respond on the way he did.

"You'd think he'd have better things to do late at night than writing abusive posts about Australian former politicians."

Turnbull has previously said the US president was unpredictable and could not be trusted to take military action if Australia, long touted as a trusted and important US ally, was attacked.

While a decision is expected within days, it's unclear whether Australia will be exempt from the US tariffs.

Australia has argued it should get an exemption because it imports more from the US than it exports - the same successful argument Turnbull used when he was prime minister during Trump's first term.

But Turnbull said the chances of another exemption were "very, very low" as the administration regretted offering exclusions the first time.

"I think this time there will be no exemptions, and they will apply right across the board," he said.

The federal government has downplayed Turnbull's comments.

"Malcolm Turnbull is not a member of the government," minister Amanda Rishworth told the Today show.

"Our government is absolutely focused on making sure that we are standing up for Australian exporters."

Opposition Leader Peter Dutton said while he didn't agree with the US president's analysis of Turnbull's term, the focus should remain on Prime Minister Anthony Albanese.

"The most important aspect now is not the tit-for-tat," he told Seven's Sunrise program on Tuesday.

"The prime minister needs to, frankly, roll his sleeves up and get this deal done so that workers jobs and the economic activity can be preserved."