Japanese Prime Minister Shinzō Abe and Prime Minister Jacinda Ardern have discussed simplifying the exchange of classified information during talks in Tokyo.
New Zealand would join only three other countries to have a security sharing agreement with Japan: the United States, the United Kingdom and Australia.
"This will make it easier for us to deepen those ties [and] continue to work together in what is quite a volatile regional security environment," Ardern told reporters in Tokyo.
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It would add to New Zealand's membership in the powerful Five Eyes intelligence alliance comprising Australia, Canada, New Zealand, the United Kingdom and the United States.
The PM touched down in Japan on Wednesday to strengthen New Zealand's relationship with Japan, which has total investments in New Zealand of $5.5 billion.
Japan is also hosting this year's Rugby World Cup which kicks off on Friday, hence Ardern and Abe's public exchange of rugby jerseys with their names written on them.
The East Asian nation is New Zealand's sixth largest tourism market with 115,000 Japanese visitors welcomed to New Zealand shores every year.
"In the face of global economic headwinds our economic relationship with Japan is becoming even more important for our economy," Ardern said in a statement.
"New Zealand and Japan enjoy a stable long-term relationship that in recent years has gone from strength to strength."
But New Zealand's commitment to its relationship with Japan is being questioned. Ardern's trip came just as the Asia New Zealand Foundation released a report suggesting New Zealand had let its relationship with Japan "drift".
China is New Zealand's biggest trading partner, following the signing of a 2008 bilateral Free Trade Agreement under former PM Helen Clark's government.
It accounts for nearly $NZ15.3 billion and 24 percent of total exports.
It didn't help that the Prime Minister's visit to Japan got off to a rocky start when she confused Japan with China in a media stand-up upon arriving in Tokyo.
Trade between Japan and New Zealand is increasing thanks to the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP), which came into force on 30 December last year.
The agreement gives New Zealand better market access to the signatories, including Japan, Canada, Mexico and Peru who New Zealand didn't have existing free trade agreements with.
Ardern said New Zealand is "already reaping benefits with New Zealand goods exports to Japan increasing by 5 percent in the first seven months of this year".
She said key products like beef, kiwifruit, honey and wine have all experienced significant growth this year, "earning millions and creating jobs at home".
The PM's visit came just as Customs Minister Jenny Salesa announced the extension of eGate access for eligible Japanese ePassport holders when arriving and departing New Zealand.
Japan joins the only other countries currently able to use eGates in New Zealand: Australia, the United Kingdom, Canada, the United States, China, France, Germany, Ireland, Netherlands and Singapore.
Ardern also thanked Prime Minister Abe for his "early support for the Christchurch Call".
"This piece of work means a lot to New Zealand in the wake of the March 15 terror attack that saw 51 innocent people lose their lives," she said in her speech in Tokyo.
"We thank Japan for being a founding supporter of the call and for engaging very constructively in early discussions."
The Prime Minister will next head to New York where she will attend the UN General Assembly and have a bilateral meeting with US President Donald Trump.