Anti-spam experts today warned of a newly discovered junk mail campaign that attempts to recruit users to a 'get rich quick' scheme by exploiting the popular fictional boy wizard, Harry Potter.

IT security firm Sophos reported that it has intercepted "thousands of instances" of an email claiming to be instructions on how to win a copy of the as-yet-unpublished Harry Potter and the Half-Blood Prince.

The emails claim that recipients can get a free copy of the book by clicking on a link, but this takes users to a website offering advice on 'free money-making secrets' and includes no mention of the teenaged wizard.

Sophos reported that the spam campaign appears to originate from the environs of Chicago.

"A lot of people are trying to make a quick buck out of the internet, and some are doing it in immoral or unethical ways," said Graham Cluley, senior technology consultant at Sophos.

"Websites like this one need to pull in traffic and prospective customers somehow, and are now using the trick of pretending to offer a copy of the Hogwarts hero's latest adventure."

Last week, author JK Rowling warned fans to beware of internet fraudsters who were phishing for credit card details by pretending to offer electronic copies of the forthcoming book.

Screenshots of this spam email can be seen here.