The Pacific Islands Forum opened in the Cook Islands with a colourful Polynesian welcome for leaders of the 15-nation grouping, who were carried aloft to the summit venue on litters. With their arrival Tuesday heralded by traditional drummers and blaring conch shells, the leaders, including Australian Prime Minister Julia Gillard, were borne to the summit venue in the capital Avarua by local warriors. Gillard, wearing garlands of flowers around her neck, waved to cheering locals 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 opening of the summit, which consists largely of small island states, came after US Secretary of State Hillary Clinton confirmed she would attend later this week. She will be the most senior US official to ever attend the PIF, in a move seen as sending a message to China that Washington intends to re-engage with the South Pacific, where Beijing's influence has grown in recent years. Climate change and marine conservation are also expected to be high on the agenda at the meeting in the Cooks, a nation of 11,000 people with 15 islands that cover a landmass barely larger than Washington DC. The absence of Fiji, which was suspended from the PIF in 2009 in the wake of a 2006 military coup, is also likely to be a major topic of discussion.