A year after the death of an Indonesian maid who was forced to sleep outside next to a dog, her mother called for justice, as several other cases of abuse languish in Malaysia's courts.

Adelina Lisao's death sparked public outrage. Her employers, a mother and her daughter, have been charged in court for murder and for hiring a foreigner without valid documents, but progress with the case has been slow.

"I have been missing my child for a year," Lisao's mother, Yohana Banunaek, told reporters on Tuesday through Skype from Indonesia's eastern city of Kupang.

"She died not because of her sickness, but because she was tortured," she added during a memorial service to mark Lisao's one-year death anniversary.

Human Resources Minister M Kulasegaran reiterated on Tuesday that Malaysia was ready to "declare war" on human trafficking and forced labour, adding that a review of labour laws was underway.

Lisao's death was among a series of high profile migrant abuse cases in Malaysia, which relies heavily on foreign workers in sectors from manufacturing to plantations and domestic work.

Malaysia is officially host to nearly two million migrant workers, though some estimates say millions more work in the country illegally, many the victims of trafficking who were duped with promises of lucrative pay.

Indonesia and Cambodia, key sources of migrant workers to Malaysia, have in the past temporarily banned their citizens from going to work in Malaysia as maids after cases of abuse.

Lisao, who was in her 20s, was rescued from her employer's home in Malaysia's northern state of Penang on Feb 10 last year after neighbours reported she had been sleeping next to a dog in a covered car parking area attached to the house.

She was found with bruises on her face and died from her injuries the next day.

"A year later there is still no justice," said Glorene Das, executive director of migrant rights group Tenaganita.

"This is not an isolated case. We have a number of cases filed in court for unpaid wages, wrongful dismissal and deductions ... but these cases just stay there."

Malaysia said last month it was mulling a separate law to protect domestic workers, a move welcomed by Tenaganita who say the group is vulnerable to forced labour due to the isolated nature of their work in a household.

The US State Department's 2018 Trafficking in Persons report put Malaysia in its Tier 2 Watch List - the second-lowest ranking - for not meeting the minimum standards in efforts to eliminate human trafficking.

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