Aluminium Bahrain (Alba) is seeking more than $1 billion in a lawsuit against US aluminum manufacturer Alcoa, alleging a 15-year conspiracy involving overcharging, fraud and bribery.

Alba alleged in the suit filed in US federal court on Wednesday that Alcoa steered payments for alumina, the key material for making aluminum, to companies abroad in order to pay kickbacks to a Bahraini government official.

The firm, which is 77 percent owned by the government of Bahrain, also alleged Alcoa overcharged it for alumina. It did not name the official to whom bribes were allegedly paid.

According to the suit filed in US District Court for the Western District of Pennsylvania, the bribes were sent through a series of shell companies controlled by Alcoa and resulted in hundreds of millions of dollars in overpayments.

Alcoa supplied the alumina from its Australian unit to a Singapore-based company controlled by Victor Dahdaleh, a Canadian citizen who lives in Britain and who, according to the lawsuit, facilitated the bribes that caused Alba to overpay for the material starting in 1993.

Alba said in the lawsuit that it was seeking damages in excess of $1 billion, including punitive damages.

"The suit was filed very late last night, so we have not had an opportunity to review the allegations," said Alcoa spokesman Kevin Lowery on Thursday. "That said, we are not aware of any wrongdoing by any of our employees or by the company."

Later, Lowery told Reuters that Alba, a 30-year customer of Alcoa, contacted the US company two weeks ago and asked Alcoa to investigate and settle the case.

Alcoa began looking into the allegations, but believed two weeks was not long enough for a full investigation, Lowery said.

"We offered to do a full investigation of our practices, but they chose for their own reasons, to instead immediately file a lawsuit.

"We plan to vigorously defend ourselves in this matter," Lowery said.

Alba became the largest modern aluminum smelter in the world when it commissioned its newest reduction line in 2005 as part of a $1.7 billion expansion project. It now has annual production capacity of more than 830,000 tonnes.

Bahrain's aluminum is exported to more than 25 countries and also went into outer space, when Alba's aluminum was used to build the Mars explorer, Sojourner. - Reuters