The secretary-general of the Pacific Islands Forum, Greg Urwin, has voiced fresh concern at the latest shipment of radioactive material through South Pacific waters.
The UK-registered Pacific Sandpiper, carrying 124 containers of vitrified high level waste, is expected to near Solomon Islands on Friday.
Forum member countries have received assurances that safety and security meet international guidelines.
Mr Urwin says even if safety isn't compromised, a scare could do economic harm.
"We have a specific though, and real worry, in respect of those situations where a ship carrying this material might be involved in an incident, an accident of some kind, which does not result in the release of harmful material, but which nevertheless, and it seems to us inevitably, will cause economic damage."
The secretary-general of the Pacific Islands Forum, Greg Urwin.
The environmental campaign group Greenpeace suggests Pacific Island governments should ask the New Zealand airforce to monitor the passage of the ships through the Pacific.