The New Zealand opposition leader has accused Australia's foreign minister of making false claims about her party's involvement in the revelation about Barnaby Joyce's dual citizenship.
Foreign Minister Julie Bishop says it would "very difficult to build trust" with a Labour government should the opposition party win the upcoming New Zealand election.
NZ Labour MP Chris Hipkins last week asked a parliamentary question - yet to receive an answer - about Australian-born people entitled to New Zealand citizenship.
It's emerged he asked the question after discussion with someone from the Australian Labor Party.
Having criticised the ALP over the incident, Ms Bishop was asked whether she could trust a future NZ Labour government.
"I would find it very difficult to build trust with members of a political party that had been used by the Australian Labor Party to seek to undermine the Australian government," she told reporters in Canberra on Tuesday.
NZ Labour leader Jacinda Ahern insisted she had been "utterly transparent" about the situation and knew nothing about the Joyce case until it broke in media reports.
"It is highly regrettable that the Australian Foreign Minister Julie Bishop has chosen to make false claims about the New Zealand Labour Party," she said in a statement.
"I greatly value New Zealand's relationship with the Australian government. I will not let false claims stand in the way of that relationship."
Ms Ahern intends meeting the Australian high commissioner later on Tuesday over the matter.
NZ Internal Affairs Minister Peter Dunne earlier said it was "utter nonsense" to suggest the question from Mr Hipkins instigated the discovery of the Nationals leader's citizenship-by-descent, which may render him ineligible to sit in the Australian parliament.
"While Hipkins' questions were inappropriate, they were not the instigator. Australian media inquiries were," Mr Dunne tweeted.
When quizzed by reporters, Ms Bishop said she didn't accept it.
Opposition foreign affairs spokeswoman Penny Wong accused Ms Bishop of risking relations with Australia's closest friend and ally.
"Minister Bishop launched an extraordinary attack on both sides of politics in New Zealand," she said.
"Australia's long and enduring friendship with New Zealand deserves better than a cheap attack by a government under pressure, seeking to divert attention from its domestic political problems."
