Jackson moved abroad soon after his acquittal

The singer was fined $169,000 (�97,000) for not paying at least 30 staff since December and letting his employer's insurance policy lapse in January.

Animals in the ranch's zoo are to be cared for by the local authority.

Michael Jackson has been living in Bahrain since being acquitted on child sex abuse charges last June.

Under Californian law, anyone employing more than one person has to have what is known as a workers' compensation policy.

An order to stop operations at the ranch was served on a security guard at the front gate but officials were turned away when they asked to see the ranch's management.

All the workers have been told to stay away and the ranch operators given five days to appeal.

Legal threat

The Neverland Ranch sprawls over 1,100 hectares (2,800 acres) in central California and as well as the main home and zoo contains a theme park.

Animals at the zoo have included elephants, giraffes, snakes, orang-utans, tigers and a crocodile.

Dean Fryer, spokesman for the state's department of industrial relations, said that Mr Jackson could reopen the ranch by obtaining workers' compensation insurance.

However, he may face legal action by the state if he fails to pay the back wages, Mr Fryer added.

The department was alerted after a Neverland employee making an unpaid-wage claim remarked that a co-worker had been injured at work and was unsure about filing a claim due to the lapsed insurance.