Australia is locked in a diplomatic brawl with New Zealand, accusing it of conspiring with the opposition to bring down the government.
The journalist told Morning Report he put questions to Mr Joyce's office, the New Zealand High Commission in Canberra and New Zealand's Department of Internal Affairs two days before Mr Hipkins' 9 August questions about dual citizenship.
However, Foreign Minister Julie Bishop says the contact between the Opposition and their cross-Tasman counterparts over the citizenship issue meant it would "very hard to build trust" with a Labour government should the opposition party win the upcoming New Zealand election.
Joyce is not the first Australian politician to get caught on this technicality in the past few months.
The question of New Zealand citizenship of Australian ministers was raised again this week after it was revealed Deputy PM Barnaby Joyce was a New Zealand citizen.
He said his father was born in New Zealand but moved to Australia in 1947 "as a British subject - in fact we were all British subjects at that time".
The Turnbull government is threatening to refer a group of Labor MPs to the High Court if they refuse to provide evidence they were validly elected with only Australian citizenship.
"I greatly value New Zealand's relationship with the Australian government", she said in a statement.More news: Perseids meteor shower: How and where to see the weekend's shooting stars
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"I can understand why they take it seriously over there because she is in a government with a majority of one", he said.
It comes as New Zealand Labour leader Jacinda Ardern hit back at Foreign Minister Julie Bishop for making "false claims" about the NZ Labour Party.
The Australian Government is moving closer towards unilaterally referring four Labor MPs to the High Court to have the validity of their election tested.
"New Zealand is facing an election", she said.
"All they need to do is produce the evidence that they are qualified to be in the House of Representatives, that they've renounced their citizenship successfully", he said.
The incident gained global notoriety when then agriculture minister Barnaby Joyce said the dogs, Pistol and Boo, had better "bugger off" back to the USA or he would have them put down.
"I wanted to make clear our level of involvement because we've been implicated far beyond what we should have been".
"This is serious when the Foreign Minister of our closest ally, Julie Bishop, unambiguously says: "Should there be a change of government, I would find it very hard to build trust with those involved in allegations created to undermine the Government of Australia".