Kuala Lumpur, Malaysia - They cannot legally work, nor send their children to school. They are at risk of exploitation, abuse - even caning. They are the 150,000 asylum seekers and refugees who have fled their homeland for Malaysia.

Harassed by police and pushed into the shadows, there are harrowing tales of months spent in detention with little food and water, the threat of violence ever present.

An Al Jazeera investigation into the mistreatment of refugees in Malaysia has sparked a parliamentary debate and an investigation by the United Nations High Commissioner for Refugees.

The documentary - Malaysia’s Unwanted - exposed allegations of abuse of refugees by Malaysian authorities and claims of corruption within the UNHCR.

101 East filmed exclusive footage inside a Malaysian detention centre, where refugees were chained and handcuffed. Refugees said they had been beaten, starved and exploited by authorities.

"The hardest thing I faced in jail was being forced to take my clothes off and then being beaten, slapped and kicked in front of others," one former detainee said.

In Malaysia, refugees have no legal protection because the country has not signed the UN Convention recognising refugees. This means they can be arrested at any time and taken to one of the country's detention centres. Kuala Lumpur has one of the world's largest urban populations of refugees and asylum seekers, with about 150,000.

The documentary also unearthed claims that UNHCR staff were involved in corrupt dealings. An illegal trade in UNHCR registration cards perpetrated by local UNHCR representatives was discovered. UNHCR said it was investigating the allegations.

UNHCR said it had long been concerned about allegations of mistreatment of asylum seekers in immigration detention centres. It said these issues were being raised directly with the Malaysian government in bilateral discussions. UNHCR said closer cooperation between the agency and the Malaysian government was needed.

Read more at: Aljazeera English indepth