The Chinese company rebuilding Bauefield Airport was stopped last month from unloading metal for fear of contamination.
But machinery and equipment on the vessel has now been brought ashore.
RNZs correspondent in Vanuatu reported this equipment may have come in contact with contaminated metal.
The opposition said the unloading happened despite the concerns of quarantine officials and farmers.
It said agriculture was a key industry for Vanuatu and to ignore regulations and offload potentially contaminated goods was a slap in the face for the sector.
