Norway's Alexander Rybak won this year's contest
Eurovision Song Contest organisers say they may ban countries from the competition if broadcasters disclose information about voters' identities.
It comes after a number of people in Azerbaijan were questioned by police after voting for a song by neighbouring Armenia in this year's contest.
Phone companies had been responsible for protecting voters' details, but now broadcasters will shoulder the burden.
Sanctions against offending countries could be a ban of up to three years.
The European Broadcasting Union (EBU) said the rule change was to ensure the protection of voters' privacy.
Last month, an Azerbaijani man told the BBC he had been accused of being unpatriotic and a "potential security threat", after he sent a text backing Armenia's song, Jan Jan.
The country's authorities said people had merely been invited to explain why they voted for Armenia.
The two states fought over the disputed Nagorno-Karabakh region in the 1990s.
Armenia's Inga and Anush perform at the Eurovision Song Contest
The EBU's director general, Jean Reveillon, said violating the privacy of voters "or interrogation of individuals... is totally unacceptable".
As it does not have the ability to penalise telephone companies, the body said it would impose sanctions against broadcasters "for any disclosure of information which could be used to identify voters".
Banning a broadcaster would effectively stop a country from being able to take part.
Norway's Alexander Rybak won the contest this year, smashing the record for the most points awarded during the competition with 387.