Arthur Fraser said the case related to the alleged attempted theft of $4m (£3.2m) in 2020 at one of the president's properties and the alleged efforts to conceal what happened.
Mr Ramaphosa said "there is no basis for the claims of criminal conduct".
Mr Fraser is seen by some as an ally of former President Jacob Zuma.
Some believe the allegations could be linked to wrangles within the ruling African National Congress (ANC) ahead of a leadership race in December.
The police have confirmed that a case has been registered with them and that "due processes will follow", which includes an initial investigation.