The games, in which viewers are encouraged to call a premium number to answer questions, like riddles or arithmetical problems, came under severe scrutiny last week after the VRT TV show Basta completed a four-month undercover operation to show that the games were rigged, making it virtually impossible for callers to win.

A Basta actor worked on one of the shows as a presenter and planted a microphone inside the production office. Basta also recruited a maths expert, who devised a computer programme to break the cipher used in the questions. But when he provided the correct answer on air, he was told it was wrong.

The investigation also revealed that producers regularly switched envelopes containing the correct answers, posed questions which had several "correct" answers and blacklisted people they knew to be capable of answering correctly.

The show in question was broadcast in the night hours by VTM and 2BE, and the Flemish Media Company (VMMA) that owns the two channels withdrew them from the airwaves.

The new rules would oblige games producers to clear their quiz questions with the Gaming Commission and ensure the answers are able to be calculated from the information onscreen. However, VMMA may not return the games to the air in any case. Games are now only broadcast by French-speaking broadcaster RTL.