Cyber criminals are using the new Harry Potter film to distribute malware, according to new research from security vendor PC Tools.

The firm said that hackers are using the increasingly popular tactic of 'black hat' search engine optimisation (SEO) to infect users keen to download the film before it is screened.

The criminals are pushing optimised links to malicious sites into the blogosphere, accompanied with text intended to attract interest, such as 'Watch Harry Potter and the Half-Blood Prince online free.'

These links take the unsuspecting user to blog site containing images of the movie and more links. However, clicking on any of these will redirect users again to a site prompting them to download and install a 'streamviewer' which contains the malware, according to PC Tools.

The firm is predicting that these tactics will be used in peer-to-peer and other file-sharing networks with increasing regularity over the coming months.

Black hat SEO manipulation attacks are becoming an increasingly common way for malware writers to cash in on a big event and spread malware. They were launched soon after the death of actor Heath Ledger, and have already been seen in the past day after the death of actress Farrah Fawcett.

Rik Ferguson, senior security adviser at security vendor Trend Micro, said that he "fully expected" to see black hat SEO techniques and spam runs using the news of Michael Jackson's death as bait to ensnare unsuspecting users.