New Zealand is preparing to present ideas to a nuclear security summit in the United States aimed at reducing the chances of terrorists getting hold of nuclear weapons.
Leaders or representatives of 47 nations have gathered for the summit in Washington called by President Barack Obama.
Prime Minister John Key has also been holding talks with top American officials on the sidelines of the summit, Radio New Zealand correspondent Daniel Ryntjes reports.
Mr Key will present New Zealand's contribution to the summit on Tuesday and says he is encouraged by the broad participation of nations in the non-proliferation efforts.
"Having 48 countries sitting around the table sharing their collective thoughts about how we might make the world a safer place has got to be a good step and a positive step - even if it's the first step."
The Prime Minister says he will not be unduly vocal about New Zealand's nuclear-free policy, as the summit is not so much about the policies of individual nations.
"We can certainly make reference to our position. It's well understood, but the important is to reaffirm that we're in a position where ultimately President Obama wants to see the world go to, which is a world free of nuclear weapons.
"But the primary purpose of this conference is actually about nuclear security. It's ultimately about the theat of nuclear weapons if they fall into the hands of terrorists."
Mr Key had a chance to speak briefly with Mr Obama who welcomed him to the US, saying New Zealand had well and truly earned its place at the summit.
Trade discussed with Vice-President
Ahead of the summit, Mr Key held talks with US Vice-President Joe Biden to discuss regional trade, nuclear security and Afghanistan.
Mr Key said the 40-minute late-scheduled meeting with Mr Biden was a chance to discuss trade issues.
"Great opportunity to reinforce our commitment to the Trans-Pacific Partnership and ultimately a free trade agreement with the United States," he said.
Mr Key says a free trade deal would provide opportunities for both countries. While the US is New Zealand's second largest market, he says, two-way trade is fairly equal even in terms of agricultural products.
The Prime Minister also spoke with Secretary of Agriculture Tom Vilsack, who indicated that US senators opposed to a Trans-Pacific Partnership free trade deal on the grounds that it could damage American dairy farmers may be open to discussions and possible compromise on the issue.
The senators are concerned about the implications of expanded market access for New Zealand dairy cooperative Fonterra and say the US could lose $US20 million over the first decade of a new trade deal.
In a statement after their meeting, Mr Biden said New Zealand was an important negotiating partner in the Trans-Pacific Economic Partnership Free Trade Agreement.
Mr Biden thanked Mr Key for his close co-operation on the nuclear summit agenda and goals, saying he appreciated New Zealand's strong support in Afghanistan, the statement said.
Mr Key says New Zealand is not going to change its anti-nuclear legislation and does not believe it hinders an improving relationship with the US.
Following calls from former prime minister Sir Geoffery Palmer for a return of non-nuclear US naval ships into New Zealand waters, Mr Key said there were no practical ways of reaching such an agreement, given that the US has a policy of not confirming or denying whether its ships are nuclear powered or nuclear armed.
"I don't think there'll be an impasse there in the short term - I don't think we should worry about that. I think its not of any great consequence, it would be symbolic and only symbolic and I don't think we should let that get in the way of an improving relationship."
New Zealand's legislation would not be changed, he said, and the US is unlikely to change its policy.
Mr Key praised the US efforts at the Washington summit to increase nuclear security.
"New Zealand brings a long long history of showing leadership in this area, arguing that the world should be free of nuclear weapons. Sure, we're a small country but we're not immune from risks like the rest of the world and we want to live in an environment where we're free of those nuclear weapons."