Australia was unwilling to ratify the protocol, but appeared to have changed its mind since its requirements were eased at a meeting in Bonn, Germany, last month.
Prime Minister Helen Clark said New Zealand shared the smaller states' concerns.
"We don't see the statement in the communique as any kind of criticism, it's simply expressing concern," she said.
"They are deeply concerned. They feel their future is on the line and they would have liked the communique to be stronger, but there was an attempt to get near unanimity and in the end Australia did go along."
Nauru and forum president Rene Harris announced that Fiji would host the forum next year, if a democratically elected government were in place.
Nauru became host after Helen Clark last year pushed to move it from post-coup Fiji.
Fiji deputy prime minister Ratu Epeli Nailatikau said he had told leaders his country was interested in hosting the next forum "provided we go through the routine of what we're supposed to do and get that right".
Helen Clark said leaders had agreed Fiji's yet-to-be elected government should re-issue the invitation which would likely be accepted, if the government and country were stable.
Members responded well to New Zealand's call for a whale sanctuary in the South Pacific - a call rejected by the International Whaling Commission last month.
Helen Clark suggested to the forum that members declare its economic zone to be whaling free.
"There was no opposition whatsoever to the recommendation put forward to proceed with the sanctuary and ... that's a huge departure from last year," she said.
Also discussed was the tax haven status of some Pacific nations, including the Cook Islands, Nauru, Samoa, Niue, Tonga and Vanuatu.
The Organisation for Economic Co-operation and Development is calling on those countries to reform their tax systems or face isolation from the international financial community - a move which has not gone down well.
"Leaders reaffirmed the sovereign right of nations to establish domestic tax regimes of their own design and choosing," the communique said.
"Leaders endorsed ongoing efforts to reach a negotiated agreement with the OECD on a tax initiative which recognises the needs of both developing and developed countries."
Meanwhile, Helen Clark was still able to raise a smile at the end of the trip home from Nauru aboard an air force Hercules.
Before the trip she said it was "marginally" better than having to row, prompting the crew to present her with a paddle as a memento.
"She laughed," a crew member said.
- NZPA
www.nzherald.co.nz/climate
Intergovernmental Panel on Climate Change (IPCC)
United Nations Environment Program
World Meteorological Organisation
Framework Convention on Climate Change
Executive summary: Climate change impacts on NZ
IPCC Summary: Climate Change 2001
