National leader Simon Bridges has refused to discuss specific changes to gun control laws but says there are likely loopholes "that can be fixed quite readily and quickly".
Prime Minister Jacinda Ardern said on Saturday that "our gun laws will change" after the terrorist attack on two mosques in Christchurch on Friday which has left 50 people dead.
In the wake of her comments, there has been reports of a rush on gun shops with people "panic buying".
Speaking to Kim Hill on Morning Report, Mr Bridges said it was up to Ms Ardern and the government to lead the discussion on gun control.
"Change is needed, I understand that, and the National Party will make sure it's a constructive party in all of this."
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However, when pushed as to what the specific changes should be, Mr Bridges was not able to say, stating: "I am no expert in this.
"There may be loopholes that can be fixed quite readily and quickly."
When asked if he would support banning military-style semi-automatic weapons, he said: "Yes, that's probably the right way to go but let's hear from the government."
"It is now for the government and the prime minister, whose roles I respect in this, to put forward those proposals."
About three years ago, the New Zealand Police Association warned members of parliament the country's gun control rules were inadequate. A parliamentary select committee recommended changes in 2017.
But the then police minister and now National Party deputy leader Paula Bennett accepted only seven of the 20 recommendations. This prompted accusations from the Police Association she had succumbed to pressure from gun lobbyists.
Mr Bridges said Labour at the time was "in precise agreement" with his party's stance.
"We are up for change," Mr Bridges said.
Gun control now needed to be "coolly and calmly but persistently looked at".
"There is, potentially, a more considered process to go through."
Mr Bridges said there needed to be an inquiry into why security agencies did not know about the attack prior.
"Could we as a nation have reasonably foreseen and, therefore, prevented this?
"What did our international partners know about and we, therefore, should have?"
Mr Bridges said there needed to be a review of the incident but would not commit to supporting a royal commission.
"It cannot simply be some second tier, second rate review or some such."