Selangor police chief Shazeli Kahar confirmed the arrest and the death of the child, Berita Harian reported.

“The two other children are being treated in hospital and their mother has been arrested for further investigation,” he was quoted as saying.

The two children are reportedly in intensive care.

All three of them were allegedly given methadone at their home in Kajang.

Methadone is a synthetic opioid often used in drug rehabilitation as a substitute for hard drugs. It eases withdrawal symptoms experienced by addicts who stop taking drugs without giving them the same “high”.

Berita Harian quoted a source as saying the incident was reported by a doctor at Hospital Tengku Permaisuri Norashikin this morning, after the three children were rushed to the hospital at about 7.50am.