Justice Minister Andrew Little has launched an extraordinary attack on the National Party, calling its behaviour over the Government's anti-terrorism bill "an absolute disgrace".
But National has shot back, calling Little arrogant and putting his ego ahead of the safety of New Zealanders.
National will today vote against the Terrorism Suppression (Control Orders) Bill, which would grant police greater powers to deal with those who have engaged in terrorism-related activities overseas if they return to New Zealand.
The bill was set to be introduced this week, but it was delayed after the Government lacked the numbers for the bill to pass; the Greens called it too tough while National had called it too weak.
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Earlier this week, Little and National leader Simon Bridges blamed each other over the failure to negotiate bipartisan consensus, which is common on national security issues.
But the impasse has been broken by the Green Party, which said it would now support the bill after the Government agreed to make changes.
Little told reporters today that he was stunned by the behaviour of National, which he said had initially committed to unconditional support of the bill's first reading, then put conditions on their support, then held unproductive meetings and will now oppose the bill.
"An absolute disgrace," Little said when asked how National had behaved.
"New Zealanders are entitled to look at the National Party and ask themselves: 'Is this a bunch of people you want responsible for the country's national security?'
"Playing party politics with national security is frankly outrageous and unacceptable."
He said when he was Opposition leader, he supported national security legislation at first reading, and sought to make any changes later.
"Frankly I'm stunned ... It is unheard of for the National Party in relation to national security to vote against it.
"The National Party has gone rogue in the last few weeks. They think that kind of tearing down the citadel and wrecking everything is some path to demonstrating to the public that they can be responsible in Government.
"That is reckless behaviour."
He today would not single anyone out for their behaviour - but he added that National's justice spokesman Mark Mitchell had always engaged responsibly.
Bridges has rejected Little's criticism and described Little's negotiating style as "belligerent".
Mitchell, in a statement, said that the bill fell short of what was needed to keep New Zealanders safe, and National will vote against it.
"Justice Minister Andrew Little has let his ego get in the way of the safety of New Zealanders. Dismissing National and our changes is arrogant and is putting the lives of New Zealanders at risk."
The bill would apply to the likes of the so-called Kiwi jihadi Mark Taylor, who is believed to be captured in Syria but could be released and try to return to New Zealand.
Under a control order, police would be able to electronically monitor a returnee's movements, restrict a returnee's access to the internet, or forbid the returnee from associating with specified people.
National had wanted the bill to apply to people aged as young as 14, and for the time limit on control orders to be extended.
Little said the chances of someone being released from a Syrian prison increased everyday, and he wanted a shortened select committee process so the bill could pass into law by the end of the year.