There has been a 100 per cent jump in the number of complaints received by the Central Bank from members of the public who have been contacted by firms offering them the opportunity to buy or sell shares in another company.

According to the Central Bank - the body which regulates all investment firms operating in Ireland - these so-called ’boiler room’ firms usually promise a very high rate of return relative to the initial investment made.

Typically the firms in question are unauthorised investment firms, operating overseas.

Shareholders in particular are often targeted by such firms who can obtain investor information by accessing publicly available shareholder lists.

According to the Central Bank, members of the public who deal with unauthorised investment firms have no recourse to the Investor Compensation Scheme, the state scheme which provides investors with funds in the event of the failure of an investment firm.

The Central Bank is advising members of the public and shareholders who receive such unsolicited contact to check the regulatory status of such firms with the Central Bank.

It notes that it is a criminal offence for an investment firm to operate in Ireland unless it has an authorisation from the Central Bank.

Members of the public can check if an investment firm is authorised, or pass on information regarding such firms, by calling the Central Bank on (01) 224 4000.