"If Australia is going to significantly ramp up its demand, then as its closest neighbour, it might look towards us to meet those demands," Reti said.
"That would be a challenge for us. That would have a negative impact on us," he said.
A spokesman for Prime Minister Jacinda Ardern raised the issue of whether the comment was appropriate with the ABC when asked to respond to Reti.
"It is not convention to comment on other country's elections and party election policies," the spokesman said.
Luxon was unaware of Reti's intervention, and wouldn't comment on whether it was appropriate.
"I don't know whether he has or hasn't - I'm not aware of it so I can't comment," Luxon said.
"I need to find out the facts and understand them," Luxon said.
Luxon said he was "concerned about the health workforce. We have had a government that hasn't been able to bring in health care workers from overseas."
"You've got both parties in Australia saying they want to put more resource into aged care sectors, and ultimately they're [the staff] going to come from New Zealand," Luxon said.
He said he was concerned about a "brain drain" to New Zealand, given the wage gap between the two countries.
Australia is in the early stages of a federal election. Labor's Anthony Albanese is trying to wrest power from the Liberal-National Coalition, led by Prime Minister Scott Morrison.
They have governed since 2013.
