By Anna Borzello
BBC correspondent in Lagos
Nigerian broadcasters are no longer allowed to show miracles on television in a way which are not "provable and believable", say the authorities.
Religion is big business in Nigeria
The National Broadcasting Commission says television stations which fail to abide by the ruling will be fined, and their equipment could be confiscated.
But no guidelines have been issued and broadcasters say they do not know how the new rules will be interpreted.
Nigerian TV is full of Pentecostal services which centre on miracles.
Many of the preachers claim to cure diseases, others to bring wealth and happiness.
But the question of how a miracle can be verified has not been answered.
Bunmi Cole, the NBC Lagos director told the BBC it would be up to each television station to decide whether or not a religious programme violated the ruling.
But the television stations are not happy with the arrangement.
Many broadcasters rely on revenue from Christian Pentecostal programmes.
Few would assume the power to judge whether or not a miracle is genuine.
The Pentecostal Fellowship of Nigeria is also concerned.
Its president Bishop Michael Okonkwo told the BBC that while there are some fake miracle workers at large, he did not believe it was the NBC's responsibility to legislate against them.
It is still not clear why the NBC decided to enforce a code which has until now been lying dormant in the law books.
However, Mrs Bunmi strongly denied a popular rumour that it was a part of a Muslim conspiracy to prevent Christians from stealing their members.