More than 45 foreign maids are facing execution on death row in Saudi Arabia, the Observer has learned, amid growing international outrage at the treatment of migrant workers.

The startling figure emerged after Saudi Arabia beheaded a 24-year-old Sri Lankan domestic worker, Rizana Nafeek, in the face of appeals for clemency from around the world.

The exact number of maids on death row is almost certainly higher, but Saudi authorities do not publish official figures. Indonesians are believed to account for the majority of those facing a death sentence. Human rights groups say 45 Indonesian women are on death row, and five have exhausted the legal process.

Figures for other nationalities are harder to come by. Rights groups say they believe there are also Sri Lankan, Filipina, Indian and Ethiopian maids facing the death penalty.

Nafeek’s execution drew condemnation from Human Rights Watch and Amnesty International, both of which have campaigned against the death penalty in Saudi Arabia. They say many migrant domestic workers, drawn to the Middle East by the prospect of employment with well-off families, face abuse.

“Some domestic workers find kind employers who treat them well, but others face intense exploitation and abuse, ranging from months of hard work without pay to physical violence to slavery-like conditions,” said Nisha Varia from Human Rights Watch. There are about 1.5 million foreign maids in Saudi Arabia, including about 375,000 Sri Lankans.

An International Labour Organisation report last week warned that an estimated 52.6 million domestic workers around the world lack legal rights and protections. But Varia said Saudi Arabia posed unique problems because legal protections were weaker and the chance of access to justice more remote.

“The Saudi justice system is characterised by arbitrary arrests, unfair trials and harsh punishments,” she said. “Migrants are at high risk of being victims of spurious charges. A domestic worker facing abuse or exploitation from her employer might run away and then be accused of theft. Employers may accuse domestic workers, especially those from Indonesia, of witchcraft. Victims of rape and sexual assault are at risk of being accused of adultery and fornication.”

Migrants are also said to struggle to gain access to lawyers and translators and it is not uncommon, according to Human Rights Watch, for the Saudi authorities to prevent those arrested from contacting their embassies.

In 2012 Saudi Arabia executed at least 69 people, says Human Rights Watch. The previous year it executed at least 79, including five women, says Amnesty International. The death toll included one woman beheaded for witchcraft and sorcery.

Amnesty said it had grown alarmed at the “disproportionate” number of migrant workers in Saudi Arabia being executed. “As with Rizana Nafeek, nearly all migrant workers in Saudi Arabia are at great risk if they end up in the criminal justice system,” said Amnesty’s Saudi Arabia researcher, Dina el-Mamoun.

“In many cases, they’re subjected to whole trials where they can’t understand the proceedings, which are conducted solely in Arabic, and without translation. They are often not given access to lawyers or to consular assistance.”

Mamoun said poor workers from the Indian subcontinent, south-east Asia and Africa did not have the contacts and influence needed to balance a justice system that was weighted against them. “All countries should be advising their residents who might be thinking of working in Saudi Arabia of the risks of mistreatment in detention, of an unfair trial and even of execution. The risks are very real and could be deadly.” Amnesty said it knew of more than 120 people – mostly foreign nationals – on death row.

Saudi officials said that Rizana Nafeek was beheaded in public near Riyadh last Wednesday. She had been sentenced to death for the murder of a baby in her care, although she claimed that the child died as a result of a choking accident.

The Sri Lankan government reacted angrily and condemned the execution. Members of the country’s parliament observed a one-minute silence in her memory. Her supporters had protested that she was only 17 at the time of the child’s death in 2005, and that international law prohibits the execution of minors. It appears that a recruitment agency falsified the age on her passport to allow her to travel to Saudi Arabia.

Sri Lankan president Mahinda Rajapaksa had requested a stay of execution to allow time for a financial settlement to be agreed with the family of the child. – The Guardian