'Foolish not to listen' to GCSB on Huawei - Collins

National says it won't be contesting a call from one of New Zealand's spy agencies to block Huawei from building Spark's new 5G mobile network.

The Government Communications Security Bureau (GCSB, which focuses on overseas threats, declined Spark's request, citing "significant national security risks".

It's not a ban - if Spark and Huawei can mitigate the GCSB's concerns, the Chinese telco may still play a role.

National leader Simon Bridges said earlier this week he hadn't seen a "smoking gun" to back up the GSCB's concerns, despite Huawei running into top-level opposition in Australia, the US and Canada - all three members of the Five Eyes spy network, just like New Zealand.

But Judith Collins on Friday said they weren't going to "politicise" the issue.

"I'm comfortable with the fact that there is advice from the GCSB, which we have not been privy to," she told The AM Show. "I always think that it would be a big call to override them when it comes to national security."

Huawei was involved in the 3G and 4G rollouts, but the sticking point for 5G revolves around how Huawei's technology works.

It's reported Huawei's systems operate largely on the 'periphery' of the network, and not the core. In previous generations of mobile networks most of the computing was done in the 'core', which in New Zealand doesn't involve Huawei technology. But the demands of 5G are greater, so more of it is offloaded to the 'periphery' - where Huawei's technology would sit.

Judith Collins and Michael Wood.
Judith Collins and Michael Wood. Photo credit: The AM Show

Huawei reportedly has close links with the Chinese government and military. Labour MP Michael Wood, appearing alongside Ms Collins on The AM Show, said it wasn't about being suspicious of China's motives.

"It's really important to say this isn't actually about China or the Chinese government, or Huawei specifically. You can go and buy Huawei products, Huawei do have infrastructure in New Zealand.

"But we have a piece of law... which means when a piece of critical infrastructure is installed, no matter who it is, the GCSB conducts an assessment and determines whether there are national security issues. They've done that in this case, and they've made their assessment... When we set up agencies with these powers, it's important we heed their advice."

He said an American or British company would have to undergo the same security checks.

"The fact is, is that if the GCSB says that there's an issue, we would be very foolish not to listen," added Ms Collins.

Minister responsible for the GCSB Andrew Little said he was "totally confident" New Zealand's trading relationship with China would be unaffected.

Spark said it was disappointed by the decision, but has no plans to delay its 2020 5G rollout.

The New Zealand China Council said it was disappointed too.

"We are not privy to the GCSB report and therefore cannot comment on its substance," said executive director Stephen Jacobi.

"We note the Government’s reassurance that this decision is about the security of a certain technology rather than about China. Even so, we are concerned that the decision may have repercussions.

"We hope the relationship is resilient enough to withstand occasional differences of view."