Huawei was founded by former People's Liberation Army engineer Ren Zhengfei and its equipment was banned from being used on the NBN, in part on advice from Australia's intelligence agencies, in 2013.

That decision was made despite the firm signing up influential Coalition and Labor figures, including Alexander Downer and John Brumby, and over the objections from some in the Coalition, including then shadow communications spokesman Malcolm Turnbull.

In addition to the domestic security concerns raised about Huawei, a 2012 US Congressional investigation highlighted the firm's links to the Chinese government and concluded that "based on available classified and unclassified information, Huawei and ZTE cannot be trusted to be free of foreign state influence and thus pose a security threat to the United States and to our systems".

But information released by a senate committee after questions from Labor senator Catryna Bilyk confirms at least 40 Huawei phones had been purchased and issued to Defence and Department of Foreign Affairs staff as of March this year.

Independent Senator Nick Xenophon questioned the decision.

"On the face of it, this seems like a bizarre decision, completely inconsistent with the federal government attitude to Huawei and the NBN," he said.

"Is the government view that Defence is less concerned about security than teenagers using the NBN?"

Security expert and head of the Centre for Internet Safety at the University of Canberra, Nigel Phair, said governments could not take their security for granted.

"You would hope that for any sensitive government communications, there is appropriate security around it, both at the end point, which is the device and the in-transit communications," he said.

"This is particularly important for Android devices (given uncurated third party apps).

"We have moved well into the era of needing to secure information - just off the cuff security just doesn't cut it anymore."

Huawei has become the world's third largest smart phone manufacturer in recent years, and the firm's Australian director of corporate and public affairs Jeremy Mitchell did not address questions about whether the firm wanted the NBN ban over turned, given the decisions to let diplomats and defence staff use the firms phones.

Instead, Mr Mitchell said that "more people are using our products and we expect that to continue as we become one of the global leaders in the smartphone market."

Fairfax Media made multiple attempts on Friday to contact ZTE, the other firm named in that months-long congressional investigation.

A total of 6495 of the company's co-branded ZTE Telstra Tough 3, a basic rugged phone that is good for use in regional areas, have been issued to Defence staff.

That 2012 report noted that both firms had argued they represented no threat to US national security interests but neither "have cooperated fully with the investigation, and both companies have failed to provide documents or other evidence that would substantiate their claims or lend support to their narratives.

The Defence Department was approached for comment.