Sydney, Australia ? An Australian man is under investigation for sending more than 2 billion junk e-mails in one year to promote Viagra, an official said Wednesday.

The Australian Communications and Media Authority began investigating the man, whose identity was not immediately released, after receiving a tip from Dutch authorities last year.

Under Australia’s 2003 anti-spam law, Australian residents who send unsolicited commercial e-mails, even from outside the country, are subject to penalties ranging from about $164,000 per day for first-time corporate offenders to about $823,000 per day for repeat offenders.

Danyel Molenaar, a project manager for the Dutch Independent Regulator of Post and Telecommunications, said the man had rented 35 servers – for more than $10,000 each per month – from a small Internet service provider in the Netherlands.

“These 35 servers were used just for sending spam day-in, day-out for at least a year, probably longer,” Molenaar said.