The closure of several Australian operations is set to cost Alcoa as much as $109 million before the year is finished, according to the company.

Alcoa revealed it had already spent $49 million on ''initial closure activities'' at the Point Henry smelter near Geelong and a rolling mill in NSW, both of which had their demise confirmed in February.

Alcoa's Portland Aluminium smelter. Credit:Joe Armao

Speaking during the company's upbeat June-quarter results in the US on Wednesday, Alcoa chief financial officer William Oplinger said another $50 million to $60 million of closure costs were expected from the Australian operations before the end of 2014.

Point Henry is due to close in August, while the rolling mills at Geelong, and Yennora in NSW, are expected to continue operating until just before Christmas.