Instead of putting out a message from President Nicos Anastasiades to welcome in 2014, it inadvertently transmitted a radio address by the man he replaced.
A CyBC statement said an inquiry was under way after "the grave mistake of inadvertently transmitting for a few seconds a New Year's message by former President of the Republic Mr Demetris Christofias".
It said management expected a prompt outcome of the internal investigation.
Anastasiades came to power in February 2013 after Christofias decided not to stand for re-election.