Thousands of domestic helpers took to the streets of Hong Kong Sunday to demand justice for an Indonesian maid allegedly tortured by her employers, the second such rally in a week.

Erwiana Sulistyaningsih, 22, was reportedly left unable to walk following eight months of abuse in the southern Chinese city and was admitted to an Indonesian hospital in critical condition last week after returning home.

Protesters including maids, rights activists and migrant group members marched through the commercial area of Wanchai, many brandishing the Indonesian national flag and chanting slogans including "Justice for Erwiana".

They handed a petition to Hong Kong Police Commissioner Tsang Wai-hun urging faster progress in the case before marching to the city's government headquarters.

"We want the investigation to speed up and we demand the Hong Kong government to stop abuses on domestic helpers in Hong Kong," Eni Lestari, chairwoman of the International Migrants Alliance and rally spokeswoman, told reporters at the protest.

The allegations have renewed concern about the treatment of domestic helpers in the former British colony following a spate of similar abuse cases and recent criticism by rights groups.

Hong Kong police had at first categorised the alleged torture as a miscellaneous case but last week launched a criminal investigation after an outcry by domestic helpers in the city.

On Friday authorities said investigators will travel to Indonesia to speak to Sulistyaningsih, who remains in hospital in Sragen on the main island of Java.

"Without this kind of protest the case of Erwiana will never go to the public or go to the court. There will be no justice," Lestari said, adding that two other maids have since come forward alleging abuse at the hands of the same employer.

The agency that employed Erwiana has said they were unaware of her injuries until they were notified by their corresponding agency in Indonesia.

Organisers claimed around 5,000 people participated in the rally, a sharp increase in numbers from a similar march on Thursday which drew several dozen protesters.

Hong Kong police were not immediately available for comment on Sunday.

The semi-autonomous Chinese city is home to nearly 300,000 maids from mainly Southeast Asian countries -- predominantly Indonesia and the Philippines -- and criticism from rights groups over their treatment is growing.

A Hong Kong couple were jailed in September for attacks on their Indonesian domestic helper, which included burning her with an iron and beatings with a bike chain.

Amnesty International in November condemned the "slavery-like" conditions faced by thousands of Indonesian women who work in the Asian financial hub as domestic staff and accused authorities of "inexcusable" inaction.

It found that Indonesians were exploited by recruitment and placement agencies who seize their documents and charge them excessive fees, with false promises of high salaries and good working conditions.

Domestic helpers in Hong Kong are paid about HK$4,000 ($515) a month.