Attempts to lift a ban on lead shipments imposed in Western Australia are now opposed by the mayor of Fremantle despite the mining company's plan to use containers instead of bulk shipping.

The ban was imposed at the Port of Esperance in Western Australia in March against the Toronto-based mining company Ivernia Inc., which has now offered to ship the metal through Fremantle using sealed containers.

But Fremantle Mayor Peter Tagliaferri seeks to block the proposed shipments because of reports of dead birds and high lead levels in the blood of locals residents.

"The risk is too high," said Mayor Tagliaferri, despite assurances that the containerising the cargo minimised the risk. "Containers can become unsealed. I just wouldn't want to run the risk, however remote. All it takes is just one to become unsealed and there is potential for disaster."

The decision whether Fremantle will be used as an alternative port for lead shipments now rests with Western Australia state authorities, who are probing the Esperance contamination, a Bloomberg report said. The state government will test seven ports for metal-pollution in their waters.

Ivernia plans to restart shipments from its Magellan mine through Fremantle by the end of the year or early next year. Ivernia is asking for community comments as it seeks state approval for the plan.

The company intends to ship 500 containers of lead through Fremantle, which is said to be the "only major commercial port" in the state that is currently able to handle the planned volume of boxes.

Fremantle is one of Australia's major bulk-cargo ports, handling grains, petroleum, liquid petroleum gas, alumina, mineral sands and other commodities. It is about 700 kilometres from Esperance, and 970 kilometres from Australia's Magellan mine in Wiluna.