HONG KONG (Reuters) - An Indonesian domestic helper told a Hong Kong court on Monday that she had been tortured by her employer, with a vacuum cleaner tube placed in her mouth and twisted to cause lacerations, public broadcaster RTHK said.

The landmark trial, featuring pictures of Erwiana Sulistyaningsih's bruised body, has sparked international outrage at the treatment of maids in the Asian financial center.

Former Indonesian President Susilo Bambang Yudhoyono denounced her treatment as torture.

Sulistyaningsih's employer, Law Wan-tung, a former beautician, faces 20 charges, including inflicting grievous bodily harm, assault, and criminal intimidation.

The public broadcaster said Law appeared calm as she pleaded not guilty to all the charges, except one, of failing to take out an insurance policy for an employee.

The domestic helper told the court, through an interpreter, that her employer had slapped, scratched, and punched her.

She said her employer had also hit her with hangers, mop handles and a ladder, and she was not paid or allowed enough food or rest, Hong Kong's public broadcaster RTHK reported.

Sulistyaningsih was only allowed to sleep from 1 p.m. to 5 p.m. each day, and given six pieces of bread and a bowl of rice, she added.

While cases of such harsh treatment are rare, Hong Kong's policies on migrant workers have made maids reluctant to report abuse for fear of losing their livelihoods and being deported.

Maids are paid a minimum wage equivalent to about $520, an attractive sum for women fleeing poverty elsewhere in Asia.

Hong Kong, a former British territory that returned to Chinese rule in 1997, has about 300,000 foreign domestic helpers, most of them from the Philippines and Indonesia.

In April, Time magazine ranked Sulistyaningsih among its 100 Most Influential People, alongside Russian president Vladimir Putin and U.S. singer Beyonce.

(Reporting by Farah Master; Editing by Clarence Fernandez)