The assembly government says one in 10 businesses have been affected
Businesses are being urged to do more to fight computer crime as police forces announce a series of measures to tackle online fraud.
It is estimated cyber criminals have cost Welsh firms around £300m over the past 12 months.
Officers and computer experts will take part in an annual e-crime summit to explain how systems can be safeguarded.
It is a partnership between the Welsh Assembly Government, police service and public and private sector bodies.
Detective Chief Superintendent Chris Corcoran of North Wales Police, chair of the e-crime Wales Steering Group said companies and individuals needed to treat online fraud as they would an "old fashion crime".
"People secure their houses and lock their windows and doors and businesses need to make sure their computer systems are secure and make sure they have anti virus systems in place," he said.
"Businesses in Wales face global e-crime challenges, as e-crime threats become more aggressive, intelligent and complex.
"The best response is to equip Wales's business community with the understanding and support they need to remain safe," said Det Ch Supt Corcoran.
Based on a recent UK Government report by the Department for Business Enterprise and Regulatory Reform, £294m was the estimated cost of e-crime to the Welsh economy in 2007.
The report added the cost to British businesses was £6 billion, with this figure likely to grow further this year.
However Det Ch Supt Corcoran estimated the cost in Wales was over £300m as not all crimes would be reported.
Hosted by the Welsh Assembly Government (WAG), seminars and workshops will be held at the conference at Newport's Celtic Manor resort.
They will focus on common e-crimes committed against businesses, the growing trend toward home and mobile working and how to do so safely and the importance of having a clear and effective IT security policy.
Research from WAG shows one in 10 Welsh businesses have been affected by e-crime. It also revealed two out of every three small and medium-sized enterprises do not have an IT policy.
Jason Hart, from security company Cryptocard will explain how people and companies can take security steps to stop the fraudsters.
Mr Hart, worked as an "ethical hacker", evaluating the security of a computer system or network by simulating an attack by a malicious hacker.
He said business people needed to understand their vulnerability and how frequently rudimentary cyber attacks took place.
"Most importantly, they need to understand that effective remedies needn't be complicated, expensive or technically complex," he said.
Also during the summit e-crime, Wales will announce its intention to appoint an e-crime sergeant.
It plans to appoint a further four police detectives in each of the four Welsh police force areas by September 2008.