Walt Disney Co has taken three Chinese firms to court over concerns local animation "The Autobots" copied elements from Disney's own hit movie "Cars", as the US firm looks to protect its drive into the world's second-largest economy. A court in Shanghai held a hearing on Tuesday, a Disney spokeswoman confirmed to Reuters. The dispute was over "copyright infringement" and "unfair competition", according to a notice on the Shanghai Pudong New Area People's Court website. Disney is making a major push into China with the recent opening of a $5.5 billion theme park in Shanghai, its first on the mainland, while its animated movies including "Zootopia" and "Big Hero 6" have been big box office hits in the country. The iconic US firm, however, faces tough competition in the market from local theme park developers, popular Chinese animations as well as counterfeits from merchandise to fake Disney hotels. Chinese authorities have promised to give Disney "special" trademark protection. "The Autobots" drew ire from netizens in China when it was released last year, with some pointing out similarities with Disney's 2006 film "Cars" starring Owen Wilson and its sequel in 2011. "Cars 3" is pencilled in to be released next year. Zuo Jianlong, the director of "The Autobots" for production company Blue MTV, told Reuters in an interview on Wednesday he was "relaxed" about a potential ruling. "Lots of people online have talked about plagiarism, but it seems from the legal side that the matter is quite clear - at root there is no plagiaristic behaviour," he said. "If you put the two films side-by-side to compare them, then you will know they are completely different." Disney declined to comment further on the case. The Chinese film is about animated racing cars including main heroes K1 and K2, while Disney's offering follows the story of legendary racing car Lightning McQueen. The three Chinese firms involved in the suit are production company Blue MTV, media company Beijing G-Point, and online content platform PPLive Inc. An official for Beijing G-Point, who gave her name only as Ms Cheng, said the firms had hoped to reach a settlement, but Disney had been opposed to this. She added G-Point was not involved in production, but rather in the film's distribution. Reuters could not immediately reach PPLive for comment. China's box office hit around 45 billion yuan ($6.8 billion) last year, and is growing fast, a lure for overseas studios to tap into the market despite a cap on imported films, censorship concerns and a rising challenge from locally made movies.