Gravel sent to French Polynesia's Mangareva island is still in port amid a dispute over whether the material is irradiated.
The ship sailed from Hao atoll and arrived in Rikitea while the island leaders said they would block the shipment to keep the peace on the island.
An anti-nuclear group Association 193 said the material which was to be used for road construction was irradiated, but the government said this was not true.
The ship has now been able to offload the gravel but it is to undergo further tests.
Hao atoll was a military base during the period France carried out its nuclear weapons tests.
The public works minister Albert Solia has said the material is ground up military buildings and hangars from the 1960s.