Workers at Apple's iPod factory in China have formed an official state-sponsored trade union.

The union, which is affiliated with the Chinese government's All-China Federation of Trade Unions (ACFTU), was set up at the Foxconn-owned factory in Shenzhen on 31 December.

Chinese law says a trade union can be formed at any place of work with 25 or more workers. Employer approval isn't required to achieve this.

The factory was reported as mistreating its employees last year. Apple investigated conditions there and said that while it found some practises went against its own ethics code, it discovered no serious abuse.

The factory employs 200,000 workers, and the ACFTU describes the unionisation at the plant as a "breakthrough", according to the TaiPei Times.