Saying that the nine-year jail term was adequate, Chief Justice Chan Sek Keong found that Aniza Essa was unlikely to re-offend and her mental illness was also 'transient'.

The 26-year-old mother of two pleaded guilty in the High Court in April last year to instigating Muhammad Nasir Abdul Aziz, then 16, to kill her disc jockey husband Manap Sarlip.

The teenager, Muhammad Nasir, repeatedly stabbed Mr Manap, 29, outside the couple's flat in Whampoa in May 2007.

Aniza was initially charged with murder, which carries the death penalty if convicted. It was reduced to manslaughter by the prosecution after psychiatric reports said that she was suffering from depression which diminished her responsibility for the offence.

Justice Chan Seng Onn jailed her nine years - a sentence the prosecution had said was 'manifestly inadequate,' prompting Attorney-General Walter Woon himself to argue for Aniza to be put behind bars for life.

Professor Woon said the Justice Chan had accepted claims that she was a battered wife and was suicidal without questioning the truth of those assertions.

Reading from the judgement, CJ Chan pointed out that Aniza's lawyer Noor Mohamed Marican had relied on the same psychiatric reports that the prosecution tendered to the court.

Mr Marican had then told the High Court that Aniza was abused by her husband so much so she instigated Muhammad Nasir to kill him.

The teenager was convicted of murder in April last year and ordered to be detained indefinitely until the President decides to release him.