The smelter and adjacent rolling mill are in Geelong, while the second mill and a recycling facility are in Yennora, New South Wales.

The smelter will close in August and the rolling mills by the end of this year.

The Anglesea coal mine and power station supplies about 40% of the power needs for Point Henry. Alcoa said a buyer would be sought after a review found the asset could operate as a standalone facility.

The restructuring charges associated with the closures are expected to be $A250-270 million after tax, with around 60% spent in the first quarter.

"We recognise how deeply this decision impacts employees at the affected facilities and are committed to supporting them through this transition," Alcoa CEO Klaus Kleinfeld said.

"Despite the hard work of the local teams, these assets are no longer competitive and are not financially sustainable today or into the future."

Alcoa said the Point Henry smelter was placed under review in February 2012, and an investigation found the 50-year-old smelter had no prospect of becoming financially viable.

The two rolling mills serve the domestic and Asian can sheet markets, which have been hit with oversupply.

The Portland aluminium smelter in Victoria will continue normal operations, as will Alcoa of Australia's bauxite mining and alumina refining operations in Western Australia.

"These are hard decisions to make," Alcoa of Australia managing director Alan Cransberg said.

"We understand how difficult this is for our employees and their families, our contractors, suppliers and community partners.

"Everyone has worked hard to improve the competitiveness of the smelter and rolling business.

"We appreciate the ongoing support of the Australian and Victorian governments and will continue to work closely with all levels of government, our employees, unions and community stakeholders to manage through these changes."

The closures will reduce Alcoa's global smelting capacity by 190,000 tonnes and its can sheet capacity by 200,000t.

Including Point Henry, Alcoa has announced closures or curtailments representing 551,000t of smelting capacity, exceeding the 460,000t placed under review in May.

Once the Point Henry shutdown is complete, the company will have a total smelting capacity of about 3.7Mt, with around 655,000t, or 17%, of high-cost capacity offline.

Alcoa shares were steady at $13.30 this morning.