Up to a quarter of online transactions could be fraudulent according to a survey published Tuesday. A global report from e-commerce solutions firm Cybersource has found that e-commerce firms are reporting up to 25 percent of online transactions are fraudulent, with an average of five percent. Three quarters of online merchants are worried that fraud is set for a dramatic increase this Christmas. While stolen credit cards and identity theft make up the majority of frauds perpetrated on the Net -- 28 percent and 20 percent respectively -- there is a worrying new trend emerging among criminals: Web sites which generate credit cards. Web-made credit cards can be accessed quickly and easily according to a spokeswoman for Cybersource. "I was shocked how easy it is," she said. "The sites are easy to find and in less than five minutes you can create a credit card." International credit card company Visa has been hit by fraud on the Internet. Although online transactions account for just one percent of its business, nearly half of complaints are generated from online transactions, according to statistics released last year. While Visa is keen to play the dangers down, a spokeswoman admits the Net is creating a new breed of criminal. "It is a new medium and that means new risks and new dangers," she said. "However our main concern is to make the Internet as safe as possible and credit card payment is the safest way of shopping online." NCIS (National Criminal Intelligence Service) is concerned enough about Internet fraud to recommend the government set up a unit dedicated to solving cyber crime. The Home Office has approved the idea but no date has yet been agreed for launching the unit. According to an NCIS spokeswoman Internet crime is on the increase. "As the Net gets a wider audience, crime will go up," she said. She denies that Web sites allowing anyone to create a false credit card means a new breed of Internet criminal is being created. "You still do need some knowledge. An average person does not have access to the complex distribution network that the professional criminal has," she said. What do you think? Tell the Mailroom . And read what others have said. See the e-commerce special for more business news.