A human rights lawyer representing the family of Nagaenthran K Dharmalingam who is on death row for drug trafficking has criticised a Singapore Home Affairs Ministry (MHA) statement that his client was not mentally "substantially impaired" when he committed the crime.

N Surendran maintained that executing anyone with a mental disability is against international law.

"Firstly, the MHA relies on the fact that Singapore courts found Nagaenthran’s 'mental responsibility for his crime was not impaired', and hence no one should object to this hanging.

"However, the MHA deliberately sidesteps the fact that the court also found that Nagaenthran suffers from borderline intellectual functioning and...