Antivirus software maker Symantec may owe the Internal Revenue Service (IRS) as much as US$1 billion in back taxes and penalties, The Wall Street Journal reports.

The IRS is seeking over US$757 million in back taxes from a company Symantec acquired last year, Veritas Software, as well as US$303 million in penalties, the report says.

At the heart of the dispute is the way Veritas shared fees and other costs with an Irish subsidiary. The IRS argues that Veritas lowered its US tax bill by crediting its US business with too much of certain technology development costs, while charging the Irish subsidiary licensing fees that were too low.

Symantec called the allegations "unreasonable," the report says, but will continue to work with the IRS to resolve the dispute.

Ireland has become a tax haven for US technology companies, according to the newspaper.