Hampton said that towards the end of last year, the GCSB received its first notification relating to 5G technology, which it must then assess from a security perspective under the Telecommunications (Interception Capability and Security (TICSA) Act.
"Following an assessment of the notification using the TICSA framework, Spark has been informed that a significant network security risk was identified.
"The regulatory process is still ongoing with Spark assessing its options," Hampton said.
Hampton said that the TICSA applied a country and vendor-neutral framework, ensuring a level playing field for all.
Hampton said the relatively new Intelligence and Security Act had made it easier for the bureau to work with the SIS including in such areas as countering foreign interference and violent extremism.
It was also helping the bureau to provide greater support to domestic law enforcement agencies than was previously possible. For example New Zealand was now able to collect intelligence against New Zealanders potentially involved in transnational crime.
He said he was now able to publicly discuss for the first time the role the GCSB played in helping New Zealand Custom.
"Through our signals intelligence capabilities, we are supporting NZ Customs to better target transnational crime networks with the aims of disrupting their efforts 'upstream' - before their activities can impact on New Zealand."
He said the new law also provided a strong legal footing for co-operating with Five Eyes partners.
"In the past year the bureau has worked with partners to make valuable contributions on cyber security, transnational crime, and violent extremism."
Rebecca Kitteridge, who has been SIS director for five years, said she had been reappointed for a further three years from May.
She said that while the national terrorism threat level was set at '"low," that did not mean no threat and the treat level was continually under review.
She said that in terms of terrorism an violent extremism, at any one time around 30 people were of particular interest to the SIS although the number was not static.
Despite ISIS losing most of its physical territory, the influence of terrorism and radical ideologies remained persistent in the online sphere.
"A small but concerning number of New Zealanders continue to engage with this often violent online content and radical ideology which presents a risk to others."
A small number of New Zealanders - men and women, some of whom were dual citizens - were likely to be in the conflict zone in Syria.
"As you can imagine, it is very difficult to obtain accurate information about the fate of those individuals because the situation is very fluid.
"We are working with international partners to obtain intelligence about any New Zealand person who may be involved in the conflict.
"In the event of a return of a foreign terrorist fighter or somebody who has travelled to the conflict zone to join ISIL, we would work closely with the New Zealand Police and other agencies."
