Amazon is deleting thousands of book reviews it deems fake, causing concern among writers.

Reports suggest that the Internet retailer is targeting reviews written by family members and other writers, although it hasn't made public as to why it's deleting the reviews or how many it's targeting.

"In some cases, the axe fell on those with a direct relationship with the author," said the New York Times, which broke the news. "In other cases, though, the relationship was more tenuous."

Several writers have voiced frustration at Amazon's behavior, such as mystery novelist J.A. Konrath.

"Customer buys book because of fake review = zero harm," said Konrath on his blog.

However, others have been campaigning for Amazon to purge fake reviews for some time. The blog "No Sock Puppets Here Please" has even started an online petition against the practice.

"The British author RJ Ellory has now confessed to posting flattering reviews of his own work and to using assumed names to attack other authors perceived to be his rivals," says the petition. "We the undersigned unreservedly condemn this behaviour, and commit never to use such tactics."

Those complaining to Amazon about the disappearance of their reviews are being sent a tersely written response. Crime fiction blogger Steve Weddle was among them.

"We have removed your review from Karma Backlash," Amazon said to Weddle after he published a review of a book written by his friend Chad Rohrbacher, on the site. "We do not allow reviews on behalf of a person or company with a financial interest in the product or a directly competing product. This includes authors, artists, publishers, manufacturers, or third-party merchants selling the product. As a result, we've removed your reviews for this title. Any further violations of our posted Guidelines may result in the removal of this item from our website."

However, despite the crusade against reviews by friends and families, many complain the reviews which are obviously paid for or are fake still remain on the site. This includes the consistently positive reviews published by Harriet Klausner who has over 25,000 Amazon reviews under her name.