The International Fund for Animal Welfare says scientists from the South Pacific are meeting in New Caledonia to assess the status of humpback whales in the region.
Marine campaigner Olive Andrews, who works for the Fund's Asia Pacific division, says Japan's move to resume commercial whaling in 2007 poses a huge threat to the migration of whales in the Pacific.
She says although the number of whales is growing in Australian waters, evidence so far suggests this is not the case in the exclusive economic zones in the Pacific.
"Places where they used to be historically abundant, such as Fiji, there are now literally no humpback whales or very little. We may have photographed several individuals over the last few years but there's certainly no viable growth of population of whales in some of these areas."
Olive Andrews says however Tonga shows a slow growth rate in humpback whale numbers of between 5 and 7 percent.