The 40 websites have been reported to Locog as selling fake or unauthorised tickets online. The figure has increased from around 15 in December 2011.
The list includes www.sportticketexchange.com, www.londonsummergames.net and www.onlineticketexpress.com.
Locog stated: "Please do not buy London 2012 tickets from any of these sites. This is not an exhaustive list of unofficial or fraudulent sites, so always use caution online."
In January, the Metropolitan Police warned the public to only use the official London 2012 website to buy tickets. The fine for ticket touts who attempt to resell Olympic tickets illegally was in February.
Locog offers an , which allows consumers to enter a URL to confirm if a website offering tickets is an official authorised ticket reseller.
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