Huawei Australia's new external lawyer, former independent senator Nick Xenophon, has launched an aggressive defence of the company, saying the telecommunications giant was being "destroyed" by "false and totally unsubstantiated claims".

The company was banned from supplying next-generation 5G mobile internet infrastructure in Australia last August because of security concerns and it announced on Monday it had secured the services of Mr Xenophon's new firm, Xenophon Davis, to represent it.

Former independent senator Nick Xenophon and his law partner, former ABC foreign correspondent Mark Davis, outside the Supreme Court in Sydney. Credit:James Alcock

"We will defend Huawei Australia against false allegations that will unfairly cause it further economic loss and reputational damage," Mr Xenophon said in a statement. "There will be no more free kicks against this company."

Mr Xenophon's broadside follows a speech delivered on Monday by Huawei Australia's chief executive, Hudson Liu, in which he claimed 1500 Australians would lose their jobs as a result of the 5G ban, which the company is making increasingly forceful efforts to persuade the government to overturn.