Leaving 5G infrastructure to the market risked "the country being left behind" because no mobile network operator would make the investment.
"It's a dead cert that's where we will end up" if a shared approach to 5G infrastructure was not taken, said McKenzie, although there was no immediate urgency for policy on the issue, which is more likely to become pressing in the early 2020s.
"There would have to be public policy appetite before you would do anything in that direction and agreement with other mobile operators."
She conceded that telecommunications sector competitors might see Chorus's position on the 5G build as an attempt to both slow down and control the rollout of 5G to allow Chorus to maximise returns from its investment in the UFB network, for which it won around 70 per cent of the rollout work.
The UFB project has used competitive bidding for a $1.7 billion revolving fund established early in the life of the 2008-2017 National Party-led government to deliver UFB to 80 percent of New Zealanders by 2022.
However, she was finding widespread sympathy for the shared approach to 5G infrastructure.
"There's a certain sort of logic to it. People sort of go 'I don't know exactly what that looks like but actually, it is a sensible thing to talk about'," said the former Telstra executive who says New Zealand is now "far ahead" of Australia for broadband speeds and consumer packages.
McKenzie welcomed the fact the new government has allowed the Telecommunications (New Regulatory Framework) Amendment Bill to proceed to select committee and said Chorus would be seeking no changes to it.
"It's been consulted on for years and to death and ended up in a place that's probably reasonable for all industry participants," she said. "Get it through and get on with it."
Chorus investors were most worried about further instability in the regulatory regime, having experienced substantial value destruction from policy changes relating to the pricing of its copper network earlier this decade.
"That's a really big overhang for us."
While taking on additional increments of the UFB rollout had both increased Chorus's capital expenditure profile and pushed out beyond 2022 its expectations of substantial free cashflows after network construction is completed, McKenzie said there was no pressure to raise additional capital.
Chorus expected to sustainably pay "modestly increasing" dividends through to 2020.
"I'm not sure that we've promised rivers of gold, because it's not quite as stable as electricity, but it (an expectation of strong free cashflow post-build) is still the right investment thesis."
The company also today announced it was experimenting in two North Shore suburbs of Auckland with a proof of concept on a Long Range Wide Area Network (LoRaWAN) IoT network that seeks to eke further earnings from Chorus's existing network of poles and copper wires.
The copper network is used to electrify localised cell sites mounted on Chorus network poles to receive data from sensors in "typically hard-to-access locations" such as underground wastewater or sewage pumping stations.
"The infrastructure's there, we've got spare copper, and it's just a way of reusing that infrastructure with interesting and innovative ideas," said McKenzie.
Chorus was testing business models for an IoT future where the company would remain a commoditised telecommunications platform provider for the "gazillion ways" that IoT applications could emerge.
It was too soon to say whether such activity could be a material earnings contributor.
Chorus shares traded at $4.04, up 1.4 per cent, today and are stable, up just 0.4 per cent, for the year.
