SHANGHAI (Reuters) - The government backers of China's largest auto show have clashed over who has the rights to organise it, sowing confusion among automakers and would-be attendees just weeks before the opening of the showpiece event in the world's biggest auto market.

'Auto China' alternates between being held in Beijing and Shanghai every year and is set to be staged this year in Shanghai between April 23 and May 2, where automakers, from Volkswagen to BYD, are expected to unveil dozens of new models and discuss company strategy.

A dispute between organisers China Council for the Promotion of International Trade (CCPIT) and the Council for the Promotion of International Trade Shanghai (CCPIT Shanghai) has spilled into the open after both issued separate notices last month saying they had opened media registrations.

A WeChat account run by CCPIT for the auto show then published a statement saying it was the official information channel. The two councils had organised the show jointly in previous years.

Executives at two exhibiting automakers told Reuters the conflict between the two organisers had sparked confusion over who they should speak to about booth displays or pay for their stand.

Last year, automakers unveiled 117 new models at the show in Beijing and put 278 new-energy vehicles on display.

The event comes at a critical time for the global auto industry this year, as it is roiled by U.S. tariffs and an escalating trade war.

Caixin reported on Tuesday that the two councils had sued each other in a Shanghai court, with CCPIT claiming that it held the right to organise the show under a contract signed in 2002. The Shanghai court, however, ruled that the contract expired in August last year, the report said.

The CCPIT appealed the verdict but the court's decision was sustained, it added. Reuters was unable to see a copy of the verdicts as they were not made public.

Two exhibitors said that CCPIT Shanghai had informed them of the verdict on Tuesday.

The sources declined to be named as the discussions were private.

CCPIT Shanghai did not respond to a request for comment from Reuters.

CCPIT declined to comment on whether it will appeal the decision again and referred further questions to China's industry ministry. The Ministry of Industry and Information Technology did not immediately respond to a faxed request for comment.

The CCPIT is a trade body backed by China's commerce ministry that promotes foreign trade, economic cooperation and trade relations between China and other countries. CCPIT Shanghai was originally founded as a branch of CCPIT but currently is backed by the Shanghai government.

(Reporting by Shanghai Newsroom; Editing by Muralikumar Anantharaman)