Makers of Tchaikovsky film reportedly self-censor their portrayal of the composer so as not to fall foul of Russia's new law

Russia's legislation banning "gay propaganda", which has already cast a cloud over the 2014 Sochi Olympics, has now reportedly prompted local filmmakers to self-censor their portrayal of the composer Pyotr Tchaikovsky, who is widely believed to have been gay.

A partly government-funded biopic of the composer of Swan Lake, The Nutcracker and the 1812 Overture will downplay his sexuality amid the homophobic political atmosphere in Russia, which passed a law in June banning the "propaganda of non-traditional sexual relations" among minors.

The film's screenwriter, Yuri Arabov, denied Tchaikovsky had been gay and said his script had been revised to portray the composer as "a person without a family who has been stuck with the opinion that he supposedly loves men" and who suffers over these "rumours", he told the newspaper Izvestiya.

The film's producer, Sabina Yeremeyeva, said it would not run afoul of the law against gay propaganda.

No one has been fined under the federal law, although charges have been filed under similar regional bans that preceded it. However, the revision of the Tchaikovsky script plays into concerns that the law will prompt self-censorship. The vaguely worded legislation includes fines of up to £2,000 for the "imposition of information about non-traditional sexual relations" in the mass media.

Kirill Serebrennikov, a respected filmmaker and the artistic director of the Gogol Theatre in Moscow, announced he would film a Tchaikovsky biopic in August 2012 but told the cinema website KinoPoisk that he was having trouble finding funding due to officials' concerns about the composer's homosexuality. In July, however, the biopic became one of the films the ministry of culture decided to finance after an open competition.

Larisa Malyukova, a film columnist at the independent newspaper Novaya Gazeta, said that in a version of the script she saw last year, Tchaikovsky suffered over his love for a younger man. Arabov's comments, however, suggested that the portrayal of the composer as gay had been edited out of the script. The Tchaikovsky screenplay went through five revisions, and the final version "has absolutely no homosexuality, it's entirely not about that", Arabov said.

Serebrennikov declined to comment, but Yeremeyeva denied that the five revisions were related to concerns over Tchaikovsky's sexuality. The producer said the controversy over the film's treatment of the composer's orientation was "overblown and made up."

Malyukova suggested that Arabov's comments are a public reaction to the political situation and do not reflect the content of the film.

"You know what kind of ministry of culture we have," she said. "Everyone is being careful, and he's being careful, and rightly so."

The minister of culture, Vladimir Medinsky, said in an interview with the news site Lenta.ru in March that "sexual preferences … shouldn't be shown, shouldn't be discussed, not on television, not in parliament, not at a rally of 500,000 people".

The state plays a major role in financing Russian-made movies, a policy that has generated an abundance of patriotic historical films in recent years. The ministry of culture is funding 30m rubles (£580,000) of the Tchaikovsky film's total budget of 240m rubles, according to Yeremeyeva.

Alexander Poznansky, who has published several books on Tchaikovsky, said "denying that he was a practising homosexual is senseless" based on the writings of the composer and his brother.

"This whole situation [with the film] is another example of the current cultural atmosphere in Russia, which makes the country a laughing stock in the eyes of the educated western public," Poznansky said.