John Key is pushing New Zealand's agenda as the final day of the nuclear security summit focuses on nuclear terrorism.
More than 50 nations' leaders are represented at the nuclear security summit in Washington.
New Zealand Prime Minister John Key spoke to leaders from the UK and India as well as US president Barack Obama.
He met with India Prime Minister Narendra Modi on the sidelines of the summit in Washington.
Mr Modi said India was the world's largest producer of milk, and New Zealand could help the processing sector there, the broadcaster reported.
He also asked Mr Key to back a campaign to have more Indian students study in New Zealand because they could feel safe in this country.
An India official said both leaders emphasised the need to have direct flights between India and New Zealand to boost tourism, while Mr Key said he wanted a free trade agreement with India as soon as possible.
Mr Key launched a strategy for India to become a core trade partner in 2011 after a joint report on the prospect.
It entered its 10th stage of negotiations in February 2015.
Mr Key also met with UK Prime Minister David Cameron today, saying that if New Zealand was on the doorstep of Europe, as Britain was, it would be looking to join the EU.
He told Mr Cameron Britain would be stronger by remaining part of the European Union.
Brits go to the polls in June to decide whether the UK should remain in the European Union.
US president Barack Obama used the opportunity of the last day of the summit to urge leaders to do more to safeguard vulnerable nuclear facilities.
He said the world needed to prevent what he dubbed "madmen" - groups like Islamic State - from getting their hands on an atomic weapon or a radioactive "dirty bomb".
The world faced a persistent and evolving threat of nuclear terrorism despite progress in reducing such risks, he warned.