"We're taking what has been said by Bob Field in his letter to us, we're taking that in good faith, that when we come to him, as we will, when we come with the committed money, that the defence will be here."
The fact that the funding would have to be provided on a basis which was acceptable to Team New Zealand "goes without saying".
Dunphy said there was still work to go to secure funding, but the fact that he was willing to put up money for short-term funding showed how confident he was that the necessary money could be found.
"People don't step up with money unless they're confident they can deliver the rest of it."
He believed the Government had indicated as part of an earlier proposal that it might have been willing to put up short-term funding of around $5 million.
Dunphy released an open letter from Kiwi Home Defence Limited - of which he is the sole director and shareholder - offering to provide support and offering to meet with the squadron and Team NZ "at any time".
Earlier, Dunphy had indicated that he had funders lined up to back a local defence, but only if Dalton stepped down. He has since softened the stance but said it was much more difficult to raise the money with Dalton in charge.
"The issue is funding of the team and my point is, for whatever reason, it appears very much easier to fund the team on one basis than another. But that's all a bit by the by because I see the team wants to go forward on one basis, with status quo and we perfectly respect that."
He would not be part of a bidding war with other cities and was now confident the cup would be held in New Zealand.
"I'm very confident that the cup will be defended in New Zealand," Dunphy said.
"If it's not there's something seriously wrong, something going on that we should know about."
Dunphy, one of the original founders of investment bank Fay Richwhite, was involved in the earliest discussions about New Zealand's attempts to win the America's Cup, dating back to Freemantle, Western Australia in 1987.
Discussions with Sir Michael Fay and David Richwhite questioned whether New Zealand had the design and sporting prowess to win the Cup.
"You just cannot imagine for any one of our campaigns that there would ever have been a suggestion that, were we to win the Cup, that we would defend the Cup offshore. It would have been heresy. And that's the proposition today," Dunphy said.
"It's our Cup, it's New Zealand's Cup. We must defend it here."