People are being warned to be aware of four unauthorised financial firms in operation.
The Central Bank says Aran Asset Management, MSIM Fund Management, and CMS ICAV have cloned the details of already existing firms.
The bank said: "It is a criminal offence for an unauthorised firm/person to provide financial services in Ireland that would require an authorisation under the relevant legislation which the Central Bank is the responsible body for enforcing.
"Consumers should be aware, that if they deal with a firm/person who is not authorised, they are not eligible for compensation from the Investor Compensation Scheme."
They added that fraudsters "are increasingly using legitimate firms’ details to add an air of legitimacy to their fraud.
"The fraudsters will 'borrow' some or all of the legitimate information of an authorised/legitimate firm for the purpose of this fraud. They may quote authorisation numbers/company registration numbers and links to seemingly legitimate websites and even provide the real address of an authorised/legitimate firm.
"Consumers are advised to check our register to verify a firm’s details and to call the firm back directly using its advertised phone number."
Meanwhile, Instant Finance Service is advertising loans on its website but has no right to do so.
The bank says the company "holds no authorisation from the Central Bank as a retail credit firm".
Anyone looking for further information can visit the Avoiding Scams and Unauthorised Activity section of the Central Bank’s website.