Security firm Websense has warned of a number of suspicious online scams designed to steal money from those donating to the California fire effort.

As with Hurricane Katrina and other recent emergencies, criminals are attempting to divert money intended for the victims by creating bogus online donation sites and advertising them on high-traffic sites.

"These criminals are trying to take advantage of the amazing outpouring of support locally, state-wide and internationally," said Dan Hubbard, vice president of security research at Websense.

"Websense is aggressively monitoring domain registrations and email honeypots, and is scanning the web for these suspicious sites."

Hubbard urged users to ensure that they are dealing with legitimate organisations by going direct to their website rather than clicking on a link in an email.

Users should remember that legitimate organisations do not aggressively approach people for money and donations, and should be wary of groups claiming to be affiliated with legitimate organisations asking for donations.

Such sites may be fraudulent or may host malicious code designed to steal information such as banking details. Online auctions claiming to support the donation effort should also be ignored.