The world's largest marine park, a vast swathe of ocean almost twice the size of France, has been unveiled by the Cook Islands at the opening of the Pacific Islands Forum.
Prime Minister Henry Puna said the 1.065 million square kilometre (411,000 square mile) reserve is "the largest area in history by a single country for integrated ocean conservation and management".
Puna said protecting the Pacific, one of the last pristine marine eco-systems, was the Cooks' major contribution "to the well-being of not only our peoples, but also of humanity".
"The marine park will provide the necessary framework to promote sustainable development by balancing economic growth interests such as tourism, fishing and deep sea mining with conserving core biodiversity in the ocean," he said.
The park was unveiled as the Pacific Islands Forum (PIF) opened with a spectacular Polynesian welcoming ceremony.
Heralded by traditional drummers and blaring conch shells, leaders of the 15-nation grouping were carried to the summit venue in the Cooks Islands' capital Avarua on litters, while flag-waving locals cheered enthusiastically.
While some leaders such as Australian Prime Minister Julia Gillard looked somewhat sheepish as they were paraded aloft before the crowd, Puna burst into song after greeting them, delighting the locals with an impromptu lounge tune.
Gillard and her New Zealand counterpart John Key wore garlands of flowers around their necks, before a spear-carrying chieftain in a headdress decorated with shells and feathers performed a customary welcoming ceremony.
Dancers in grass skirts added to the Polynesian pomp for an event organisers said was one of the largest in the nation's history, rivalled only by a visit from Queen Elizabeth II in 1974.
"This is certainly the biggest thing to happen here for decades," one official at the ceremony told AFP.
The Cook Islands protected zone will be the largest single marine park in the world, taking in the entire southern half of the nation's waters.
The 15 islands have a combined landmass of 240 square kilometres (93 square miles) -- barely larger than that of Washington DC -- but its waters include environmentally valuable coral reefs, seagrass beds and fisheries.
Marea Hatziolos, the World Bank's senior coastal and marine specialist, said the Cook Islands' initiative was a win for both the environment and the country's economy as it would help save fish stocks and promote tourism.
"There's definitely an economic dimension to this, apart from protecting biodiversity," she told AFP. "It allows small Pacific nations to generate revenue."
US Secretary of State Hillary Clinton will attend the summit later this week, in a move seen as sending a message to China that Washington intends to re-engage with the South Pacific to counter Beijing's influence in the region.
Australian Prime Minister Julia Gillard said Clinton's attendance showed "how deeply engaged America is in our region".
The absence of Fiji, which was suspended from the PIF in 2009 in the wake of a 2006 military coup, will also be a major topic of discussion.
Australia announced in June that it was creating a network of marine parks covering 3.1 million square kilometres, more than a third of its territorial waters. However, they are dotted around its huge coastline.