The Pentagon has agreed to send a group of Marines to New Zealand next year after an invitation from Prime Minister John Key.

Mr Key also invited the United States to consider sending a Coast Guard ship.

The Marines' visit will be ceremonial only and they will not be exercising with New Zealand military. They will be visiting to mark the 70th anniversary of their arrival in NZ during the Second World War in 1942, to defend New Zealand against potential Japanese invasion.

Mr Key confirmed the visit by the Marines after meeting US Defence Secretary Leon Panetta in Washington and he said it would be a way to thank the Marines for what they had done.

He said the government would work with the Royal returned and Services association "on the best way to show New Zealand's gratitude."

The US has all but restored the relationship after a 25-year rift over New Zealand's anti-nuclear legislation.

In 2009 the US dropped its own ban on military exercises with New Zealand and it restored the full intelligence sharing relationship.

But Navy visits are off the agenda for the foreseeable future.

Mr Key said he raised the issue of a Coast Guard ship visit with Homeland Security Secretary Janet Napolitano and Mr Panetta.

"I didn't ask them for a response" he told reporters. He had made it quite clear that this was an issue which was worth consideration given their work together in Antarctica and in the Pacific.

New Zealand Ambassador to Washington Mike Moore was the driving force behind the bid to get the Marines to New Zealand.

It could see a march though Lambton Quay by the marines, an event that would be charged with symbolism to accompany the as the relationship gets back on to an even keel.

Almost 50,000 Marines based themselves around Wellington at a time in the Second World War to help to defend New Zealand against a potential Japan attack.

At any one time there are about "half a dozen" marines stationed at the US embassy in Wellington, according to embassy staff.

Debt crisis forces cancellations

Meanwhile the two senior Democrat and Republican Senators that Mr Key had been due to meet today pulled out because of the debt ceiling crisis.

Democrat Harry Reid and Republican Mitch McConnell are in the thick of negotiations with colleagues and President Barack Obama to raise the Government's $14.3 trillion debt ceiling by August 2 to avoid running out of money.

Senator John Kerry, the chairman of the foreign relations committee and Republican Senator Richard Lugar stood in for them and greeted Mr Key.

Meetings with the money men

Mr Key also met with Treasury Secretary Tim Geithner and Federal Reserve chairman Ben Bernanke as well as Senators and Congressmen.

"All of the meetings today have been signified by a great warmth - not just outside," he said in reference to the heat wave in Washington "but inside as well."

"We have been very much welcomed as a real friend and strategic partner, as somebody that works alongside and shares the same values and principals of the United States of America."

Mr Geithner had reaffirmed his commitment to a Trans Pacific Partnership.

Mr key said a very useful discussion with Ben Bernanke "About the state of the economy at the moment, the nature of the recovery, the challenges that they face."

Both Mr Bernanke and Mr Geithner had been very "frank, open and honest with us,"

"It is a very sensitive time here in the United Sates and it would be useful for me to characterise actually what they said to me but they were very open."