In his speech, Labour leader David Shearer spoke of the need for China to be included when aid donors were working in the region.
He said although the Pacific region was a "picture postcard" it had development problems.
"Achieving better results for the Pacific also requires that old and new donor nations work together and support each other. It is important not just to work with countries like Australia, Japan, and the EU, but also China, which is on-track to become the world's largest economy.
"We have to work cooperatively with all of those partners."
However, NZ First leader Winston Peters urged caution over the seductive pull of China, saying the region was becoming an area of "competing influence", and that created a sense of disquiet. He said that competition was partly because of the region's proximity to Asia, its natural resources, and the number of UN votes it held.
"We all know how seductive it is to be taken down the main drag in China, with motorbikes in front and motorbikes behind, and treated like you are a god ... That seductive experience in the Pacific, with Asia, has to be carefully handled."
Mr Peters said it was in New Zealand's interests for the Pacific region to flourish.
"We understand that poverty and social ills lead towards political and social unrest. We want a stable region that is prosperous, with strong trade links and a strong diffusion of ideas."
He also urged those countries not to put aside their own cultures for the sake of others, saying that he personally believed in institutions such as Fiji's Council of Chiefs.
National's John Hayes, who chairs the Foreign Affairs Select Committee, said the Forum was organised to reinvigorate the relationships between the Pacific countries and discuss issues ranging from the strength of democracy to the environment. He said while it was not New Zealand's place to dictate how other countries managed their affairs, it was its responsibility to work with neighbouring countries.
"Any instability in the neighbourhood has consequences for us all. We each have our part to do. The future wellbeing of your community is tied to mine. We are joined together like a plaited rope."
While many of the delegates are MPs, those invited to attend from Fiji include two political party representatives and two community leaders, rather than members of the Fijian interim government. The delegates will hold discussions and debates on issues such as climate change and the role of the media on Friday and Saturday, before a field trip to a Wairarapa orchard which is currently home to workers from the Solomon Islands who are on the Regional Seasonal Employment scheme.
