Each Welsh police force has an officer dedicated to tackling e-crime
The number of victims of cyber crime in Wales has more than doubled since last year, an online safety group says.
e-Crime Wales said there had also been a 67% increase in security incidents such as attempted password hacking, data loss and spreading viruses.
The cost to businesses is estimated at £373m based on 2009 turnover figures.
One businessman had e-mails stolen while on holiday and 15 years of records copied by a former employee, who was later caught and prosecuted.
Since September 2008, each police force in Wales has had a dedicated officer working to combat e-crime in the country, making it unique in Europe.
Research by e-Crime Wales, which promotes online safety to businesses, shows companies are becoming more aware of online risks, with more than half increasing their spending on IT security in the past year.
However, as they become more dependent on computing and new developments like cloud computing, where data is saved online, they are also vulnerable to new types of cyber crime, the group says.
e-Crime Wales police manager Andrea Barnard said: "We're committed to making Wales a safe place to do business online.
"But e-criminals are highly resourceful, and as they're not bound by the same laws and regulations they're forever one step ahead of the game, finding new ways to attack and compromise businesses.
"E-crime is always evolving so businesses need to stay vigilant to the latest solutions to ensure safe trading, and businesses in Wales have a unique opportunity to take advantage of the free of charge resources e-Crime Wales has to offer."
Nigel Perring know from first-hand experience the problems technology can bring with it.
His small chartered surveyor's firm had an employee of four years who had designed their IT systems but was made redundant in 2008.
Shortly afterwards, Mr Perring went away on holiday for a week unplugging his computer and putting it away for the duration, but when he returned he discovered he had not received any e-mails at all for one of his accounts for that week.
On investigating, he found that his e-mails had been downloaded from his internet service provider (ISP) to another computer in Cwmbran, where the former employee lived.
Gwent Police were brought in and their high-tech crime unit investigated. They interviewed Mr Perring's ISP and his former employee's ISP, and eventually prosecuted the employee under the Computer Misuse Act for the theft of the e-mails.
However, on further investigation using newly developed software, they discovered the ex-employee had downloaded 15 years' worth of records from Mr Perring's computer, with the intention of setting himself up in a rival business.
Mr Perring, 56, said in the end the employee was only prosecuted for the theft of the e-mails, but added he had felt more affected by the stealing of other data.
"I feel as though someone's broken into my office and stolen my files. I feel violated."
His company has now tightened its computer security and changed all the passwords. However he added: "It's been a salutary lesson to me.
"Because computers are a relatively new thing to my generation, we're still getting used to them."
e-Crime Wales will be holding its annual summit on helping businesses protect themselves at the Celtic Manor Hotel in Newport in July.