The bank has named 295 firms since August 1998
The Central Bank has issued a warning to consumers about an unauthorised firm, Kennedy Kilbride (UK).
The bank says Kennedy Kilbride (UK) is not authorised as an investment firm, investment business firm or to provide investment advice.
In a statement, the Central Bank says: "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."
Anyone who has information about such firms can contact the Central Bank on 01-224-4000.
The bank has named of 295 unauthorised firms since August 1998.
A list of unauthorised firms is available on the Central Bank website.