A Turkish court has asked experts to determine whether the "Lord of the Rings" character Gollum is good or evil to decide whether a doctor insulted Turkey's President Tayyip Erdogan, the defendant's lawyer told Reuters on Wednesday.

Erdogan's lawyers are suing Bilgin Ciftci, a physician from the western city of Aydin, after he shared pictures on social media of the president juxtaposed with those of the "small, slimy creature" immortalized in J.R.R. Tolkien's fantasy novels.

"The prosecutor didn't watch the movie and he defined Gollum as 'the monster in a bad role'. But we said Gollum can't be defined as evil. The character itself is a war between good and bad. He is basically seen as a victim of society," said Ciftci's lawyer, Hicran Danisman.

"The judge said he was familiar with the movie but he couldn't decide whether Gollum was good or bad," she said.

The experts who must decide the issue include a cinema specialist, a behavioural scientist and a psychologist, Danisman added.

Gollum appears in Tolkien's tale "The Hobbit" and in his "Lord of the Rings" trilogy, which have both been turned into blockbuster movies.

Gollum is depicted as both an antagonist of Tolkien's heroes, the hobbits Bilbo and Frodo Baggins, and also as a victim of a powerful magic ring that has twisted his body and mind.

In Turkey, insulting the president is a crime punishable by up to four years in jail.

Erdogan, who has dominated Turkish politics for more than a decade, brooks little dissent and has sued dozens of people, including cartoonists, a former Miss Turkey winner and teenagers on accusations of insulting him.