Also on Monday, Mr Xenophon rejected suggestions that he should have registered on the Foreign Influence Transparency Register, saying Huawei was not a foreign entity and he was not a lobbyist, therefore he had no need to register.

Senator Patrick is former senior adviser to Mr Xenophon, and took over his Senate spot when Mr Xenophon resigned in late 2017.

Senator Patrick has pushed hard for an inquiry into all aspects of China's relationship with Australia - from its investment push into the Pacific, to its influence in universities, critical infrastructure, mines and other resources, and its suspected role in major cyber attacks.

But Senator Patrick dismissed questions about whether Huawei's engagement of Mr Xenophon had anything to do with the outspoken stance he had taken on China in the Senate.

"I wouldn't think that at all," Senator Patrick said. "We rarely talk to Nick."

Mr Xenophon left the Centre Alliance shortly after his failed bid for the South Australian Parliament in early 2018 to pursue a private sector career.

"He respectfully has left us to do the job that we do in the Senate," Senator Patrick said.

"Obviously, when he first resigned I talked to him a fair bit, but as time has marched on he's very confident with the job that we're doing and there's very little need for us to talk."

Mr Xenophon was a private citizen and free to work for Huawei, Senator Patrick said.

But the former colleagues do not see eye-to-eye on Huawei, which was angered by Australia's decision to ban it from bidding for the rights to operate the country's 5G wireless network.

Senator Patrick said he accepted the view of security agencies, which had way more information than him, but Mr Xenophon said Huawei had been treated very poorly.

"They have just taken it on the chin and I think they're sick of it," he said. "This is about setting the record straight."

Mr Xenophon also rejected the suggestion that his appointment was related to Senator Patrick's role in the Senate.

"Anyone who knows Rex will know that he's fiercely independent in his approach to issues, and I have never sought to influence him on any issues in the past," he said.

"... My job is a lawyer, not as a lobbyist, and other than having a very respectful relationship with Rex there are others that can lobby him on behalf of Huawei. It won't be me."

Mr Xenophon said he and former journalist Mark Davis had been taken on by Huawei not to lobby politicians but "to give advice to Huawei, to advocate for them, and to correct the record if there has been a malicious falsehood said about them."

That was very different from lobbying, which involved knocking on doors, he said.

On the 5G network, he said the irony was that Huawei's competitors would source equipment from Shanghai Bell, half-owned by the Chinese state, which would create a direct link to the Chinese government. And he said US President Donald Trump's recent suggestion that he might lift his ban on Huawei said much about the substance of the ban.

European security agencies had put in place robust safeguards when it came to Huawei and Australia could do the same, he said.

Prime Minister Scott Morrison, announcing an $88 million taskforce to tackle foreign interference, said the government stood by the decision it had made on Huawei.

"It was a decision that applied across any number of those who would have sought to make applications that would have fallen foul of the standards that we set," Mr Morrison said.

"So, look, I wish Nick all the best in his new employment and sounds like he's prosecuting his case. It's a free country."

Mr Xenophon said he started with Huawei in October.