The BBC is investigating allegations that actors were hired to pose as members of the public featured in reality TV show The Real Hustle.
The BBC Three programme features a team who con members of the public in order to show viewers how frauds work.
Objective Productions makes the show for the BBC and said it "categorically" denied claims in the Mail on Sunday that the "victims" were briefed.
The firm said: "All the people on the show have been hustled for real".
In a statement, it added that "their reactions are genuine".
"We have never employed an actor as a 'mark' [victim of a hustle], briefed them in advance and asked them to fake their initial reaction to the scam.
"Occasionally, because of, for example, equipment problems, we have had to re-shoot short elements of the set up after the hustle has been completed and that can involve giving some direction to the 'marks' to ensure that the footage matches.
"However it is completely untrue to say that any 'mark' was an actor who was fully briefed in advance and paid to act as though they had been hustled."
The BBC said it was "of paramount importance to the BBC that our audiences are not misled by the programmes we broadcast".
A BBC spokesman said: "We will examine any alleged breaches of our editorial standards relating to The Real Hustle as a matter of urgency and will take appropriate action if required."