International fraudsters are bombarding Irish businesses and have stolen more than €4.4million in online scams so far this year.
Some of the thefts were perpetrated after they saw business bosses targeted when they were spotted on social media.
The huge toll has hit dozens of businesses in Ireland from huge global firms to even a householder buying a garden shed.
The scams were revealed in an update by the Garda National Economic Crime Bureau at a briefing inside their headquarters.
Past victims of so-called CEO fraud and invoice redirect fraud have been Dublin Zoo and Meath County Council but now sports clubs, pubs and farmers have joined the list of victims.
The gardai also revealed that the figures ranged from €700 to $1m through an Irish based company through compromised emails.
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Chief Superintendent Pat Lordan said: "Stop and think before you change bank account details for anyone. Ask the question is this really the person or company you owe money to. Pick up the phone and speak to the person concerned."
"We need to create an alert for the public, not just for the businesses. It is basically focused on invoice redirect fraud and CEO fraud and business email compromise.
"The reason we are here today is because we have seen a marked increase in this frauds and the figures are quite dramatic.
"Over four and a half million lost this year through fraud and that is effecting 120 different businesses and individuals - our fear is that if this continues people will lose jobs and businesses will close."
Superintendent Michael Cryan revealed that since the start of January there have been 132 reports to the GNECB across the country.
Of the €4.4m gardai have recovered €1.28m in swoops on financial institutions before the criminals could withdraw the cash.
He said: "In April alone there have been 39 reports to us - for example one would be where a company received an email from a customer saying they must change accounts.
"This led to one company transferring $1m US Dollars - but this was reported very swiftly and An Garda Siochana, in conjunction with the Financial Intelligence unit in Hong Kong were able to recover the money."
A new attack was a when a HR manager recieved a fake email from the managing director asking that his wages be sent to a different bank account."
Chief Supt Lordan explained how the fraud works.
He added: "They ask you very nicely can you change his bank account details on your system.
"The criminals know the CEO i away for the week because he has posted it on social media.
"An example of the wording on one of the emails was 'please, complete process of same day payment urgently, let me know when you are available and how soon you can do it'."
The gardai have appealed to business and the public to contact them if there is any suspicious activity and to bring an end to the frauds.
