"It's not guaranteed to be here ... there is no formal reciprocal agreement," said New Zealand Rugby League chief executive Greg Peters.
He said the match will be in Australia for "commercial reasons".
It's a shame, as the Kiwis have hosted the Kangaroos only three times in the past decade (2012, 2014, 2018) but Peters argues the decision is pragmatic.
The NZRL need to shore up their reserves ahead of next year, when their revenue-earning opportunities are limited due to the World Cup.
Having the game in Australia means the NZRL will gain a match fee but won't have to wear the costs and risks associating with staging the event.
But it's a shame for local fans, and also for Maguire and his team, as the chances of success are always higher in front of a home crowd.
The Kiwis will play three more matches in 2020.
There will be another rematch with Tonga, which is evolving into New Zealand's version of State of Origin.
That's scheduled for June 20, and almost certainly in Auckland, given the city's large Tongan population, although Peters insisted the venue had yet to be decided.
As part of the Oceania Cup, the Kiwis will also face Fiji on October 24 in New Zealand.
It will be just the second clash between the two nations, after the infamous 4-2 quarter-final defeat of the Kiwis in Wellington at the 2017 World Cup.
Maguire's squad will then face Papua New Guinea in Port Moresby on October 31.
It will be the first trip there for a New Zealand team since 1994, when Frank Endacott's side won both their tests.
It was previously a regular stop, as Kiwis teams made five tours to Papua New Guinea between 1978 and 1990, and Peters hopes it will again become a fixture on the Kiwis calendar.
"It's something we would like to do more of in the future," he said.
Following on from last year, the Kiwis Ferns will also have an extended schedule in 2020.
They will again play a mid-year test, as well as a clash with the Jillaroos to bookend the men's international fixture on the same night in October.
And the Ferns will also join the Kiwis on the tour to Papua New Guinea.
"It's an important year," said Peters. "We want to keep the momentum in the women's game that we built up last year.
"For the Kiwis, we will be part of the Oceania Cup, with an eye to getting the squad to a point where Michael Maguire has a good group of people to select for the World Cup," said Peters.
"For both teams, it's a big year for the players coming through, who can challenge the more established Kiwis and Kiwis Ferns."