Workfair Singapore, which works for the welfare of local and migrant workers, said Wednesday that the allegations were "extremely grave" and deserved "the full investigative weight of the authorities".
According to customary international law, statements obtained by coercion or under duress may not be used in evidence.
The group has called on Singapore's Law Minister K. Shanmugam to appoint an independent investigator with full access to all the arrested persons and police officers.
The group also expressed concern about the 53 people who face deportation to India.
"We call on the minister for home affairs to stop the deportation and either submit these accused to trial or issue them with warnings as has been done with 200 others whose involvement was deemed to be 'relatively passive'," it said in a statement.
The riots broke out after an Indian worker, Sakthivel Kumaravelu, died Dec 8 after being run over by a bus in the Little India neighbourhood.
Mobs attacked officers who responded to the accident call in what was the biggest riot in Singapore in some 40 years.
--IANS (Posted on 18-12-2013)