In a rare move, the Court of Appeal yesterday ordered a review of its decision two years ago to convict a 32-year-old Nigerian man who was initially acquitted of bringing nearly 2kg of methamphetamine into Singapore.

This comes after the defence filed a criminal motion to reopen the case by relying on a psychiatric report prepared by the prosecution for sentencing arguments.

In a written judgment, the same panel of three judges who had overturned the acquittal of Ilechukwu Uchechukwu Chukwudi said they agreed to allow the request by his lawyer Eugene Thuraisingam to review their decision "due to the unique turn of events" at a very late stage of the proceedings.

The report by Institute of Mental Health (IMH) psychiatrist Jaydip Sarkar, issued in March, said Ilechukwu suffered from post-traumatic stress disorder (PTSD) - a result of childhood trauma that came from witnessing tribal killings.

Dr Sarkar said PTSD symptoms were triggered after Ilechukwu was told by Central Narcotics Bureau (CNB) officers that he faced the death penalty, causing him to lie in his statements.

The psychiatrist said the disorder was "likely to have led to an overestimation of threat to his life, which could have prompted him to utter unsophisticated and blatant falsehoods in order to save his life".

The court said Dr Sarkar's opinion contradicted key parts of its 2015 decision to convict Ilechukwu after it found no explanation for his lies other than "his realisation of his guilt".

The court - comprising Judges of Appeal Chao Hick Tin, Andrew Phang and Tay Yong Kwang - said it was prepared to accept this report, until proven otherwise, as "compelling" material that warranted a review.

The court referred to its judgment in the high-profile case of Sarawakian murderer Jabing Kho, in which it ruled that review of concluded criminal appeals would be allowed "only in truly exceptional cases". Kho was hanged last year after a series of failed attempts to reopen his conviction.

Yesterday, the court said: "The present motion is, in our view, such a 'truly exceptional' case because of the unique turn of events.

"It is entirely fortuitous that the IMH report... has raised a matter which has a crucial bearing on our decision."

The court added that it was not making a finding that Ilechukwu does indeed suffer from PTSD or that he was affected by it when he made his statements to the CNB.

"We are likewise not implying that he is innocent. His guilt or innocence is a matter to be determined at the subsequent review of our decision," the court said.

The case will be sent back to the trial judge to receive evidence and make findings on several issues, including whether Ilechukwu indeed suffered from PTSD and the extent of its impact on statements.

Ilechukwu, who arrived in Singapore from Nigeria on Nov 13, 2011, passed a suitcase to Singaporean Hamidah Awang, who placed it in her car and drove to Woodlands Checkpoint, where the drugs were found in the bag.

Ilechukwu was arrested in his hotel room the next day.

In November 2014, Ilechukwu was acquitted by Justice Lee Seiu Kin, who accepted that the Nigerian did not know the suitcase contained drugs. The prosecution appealed to the Court of Appeal, which overturned the acquittal.

The Government recently proposed measures aimed at preventing abuse of the court process and the waste of judicial resources by people trying to reopen their criminal cases after exhausting all avenues of appeal.

Mr Thuraisingam told The Straits Times: "My client looks forward to vindicating his position before the trial judge with the fresh evidence."