Although now formalised, the deal was flagged by Spark late last year when chief executive Jolie Hodson confirmed her company's "multi-vendor" team had been expanded to include the Korean giant.
Spark began its 5G rollout late last year by launching 5G fixed-wireless (5G as a landline substitute) in a series of small South Island towns - using Nokia Networks (Vodafone NZ's primary network technology partner) for the radio access network (RAN or the edge or celltower elements), and Sweden's Ericsson and US company Cisco for different elements of the core - or brains for the network.
Last month, Spark said Huawei remained a preferred partner, and that if it decided to use the Chinese company's gear, it would re-submit a revised proposal to the GCSB.
Huawei NZ took heart last month when the UK government gave its operation there the green light for limited participation in that company's 5G network upgrades.
But in comments to the intelligence and security select committee on February 12, GCSB director-general Andrew Hampton said NZ was following its own process.
His comments made it clear that he was at loggerheads with Huawei over the Chinese company's claim that the edge and core of a 5G network can be securely separated, which it says has been proved in lab testing with Spark and elsewhere.
Hampton told MPs the distinction between the edge and sensitive elements in the core was "blurry" with 5G.
"Indeed, that's intentional: that's what 5G is: you distribute the important parts around the network so it works faster," Hampton said.
A 5G auction for temporary spectrum is due to start on March 30, and Spark's 5G mobile rollout on July 1.
Vodafone went live with 5G for 100 cell sites around Auckland, Wellington, Christchurch and Queenstown in December, and is now in-filling its network, working with Nokia Networks.
2degrees, which has Huawei gear in both the edge and core of its 4G network, has yet to detail a timetable for its upgrade to 5G.