The Pacific Invasives Initiative says countries need to prioritise prevention as the best method of protecting against pests.
The Initiative is a partnership made up of eight organisations throughout the region.
Its Project Coordinator Bill Nagle says otherwise, eradication and controlling a pest are too costly.
He says work in Tokelau has seen an ant invasion now under control, and efforts to stop mynah birds increasing appear to have been successful.
Mr Nagle says there's no room for error in managing a pest once it exists.
"We've had what looks like a very successful rat eradication off a small island in Fiji, and that's led already to an increase in sea birds and some of the lizards on the island. We've had another major baiting project on another island off Viti Levu in Fiji. And we now have a monitoring programme in place - and about another 14 projects."
Bill Nagle says NZAid has just granted the group funds for another three year term, given its progress.