An atheist faces jail in Russia for insulting the feelings of religious believers by denying the existence of God.

Viktor Krasnov, 38, appeared in court in southern Russia on Wednesday after declaring in an online exchange in 2014, "there is no God", the Guardian reports.

"If I say that the collection of Jewish fairytales entitled the Bible is complete bull****, that is that," he wrote on a local website in his home town of Stravropol.

"At least for me," he added, "there is no God!"

He was then reported by someone involved in the debate for "offending the sentiments of Orthodox believers".

Krasnov is being prosecuted under a law introduced in 2013 after the punk band Pussy Riot was jailed for a performance in Moscow's main cathedral, his lawyer Andrei Sabinin told AFP.

Two members of the band were arrested and charged over inciting religious hatred and violations of public order. They were protesting Putin's return to power and criticising Russian authoritarianism.

Krasnov's charges carry a maximum sentence of one year but he has already spent one month in a psychiatric ward undergoing examinations before he was deemed sane. His lawyer told AFP his client was "simply an atheist" and that "Halloween and Yiddish holidays" were also targeted in the exchange.