The Central Bank has warned shareholders about the dangers of ''boiler room scams''.
If people receive unsolicited approaches from a firm which offers them services to purchase shares in another firm, they should check the regulatory status of such firms with the Central Bank.
In March, the Irish Stock Exchange warned investors to be vigilant to potential scams targeted at shareholders in Irish companies.
It said that if an offer sounds too good to be true, it probably is.
The Central Bank said today it has seen a 100% increase in the amount of queries and complaints from members of the public who have been contacted by foreign unauthorised investment firms who offer the chance to buy shares in another company to to sell existing shares they have. This usually involves an upfront fee.
Fraudsters contact investors unexpectedly and offer to buy their shares at prices higher than current market values in these ''boiler room scams''. These people obtain investor information and contact details by accessing publicly available shareholder lists.
The ISE said that while cold-calling by phone is the most common form of contact, they may also use email, post, face-to-face contact or approach investors at seminars.
The Central Bank stated today that it is a criminal offence for an investment firm to operate in Ireland unless it is authorised by the bank. Clients who deal with such firms have no recourse under the Investor Compensation Scheme.
A list of all warning notices issued by the Central Bank on unauthorised investment firms is available on www.centralbank.ie.
