The Australian Security Intelligence Organisation has refused to say why it allowed Chinese telecommunications provider ZTE to tender for the NBN but recommended banning Beijing-based rival Huawei.
The ZTE green light was revealed by SC's sister publication CRN this week when Australian managing director Leo Zhenyu said the company had engaged in "several conversations" with government agencies, which approved it to bid for the NBN. ZTE said initially it had spoken with ASIO but later retracted the statemment to say it had not been in conversations with the security agency.
This is despite the government relying on ASIO to inform it of rival Huawei's security credentials.
"Any ASIO advice to government on critical infrastructure protection, including telecommunications matters, is confidential," ASIO told SC in a statement.
The Federal Attorney-General's Department said it took a "considerable interest" in the security and resilience of the NBN and directed further requests to ASIO.
Last year the Australian Financial Review revealed Huawei was banned from bidding on the NBN on advice from ASIO.
Reuters reported a White House review last year found Huawei kit contained vulnerabilities.
Two unnamed officials familiar with the US intelligence assessments told Reuters government agencies were concerned with the capability for future spying or sabotage but no past malicious activity had been discovered.
But further unnamed sources told the news outlet Huawei kit was "riddled with holes".
German security researcher Felix Lindner said the vulnerabilities in Huawei kit were more likely the result of sloppy coding than deliberate attempts to install backdoors.
A separate US senate committee last year claimed both telcos had sold compromised equipment with chairman Michael Rogers claiming Huawei and ZTE kit had “backdoors and unexplained beaconing".
But ZTE executive director Alain Saaroni told CRN ZTE’s dual stock exchange listings in Hong Kong and Shenzen meant the company was viewed as more transparent than its rival.
Huawei has rejected criticism that Huawei's chief executive officer Ren Zhengfei's former role as a civil engineer in the People’s Liberation Army was evidence the company was controlled by Beijing.