SINGAPORE - A 39-year-old man who has served time for eight years for heroin trafficking had his jail sentence reduced by 12 years on Thursday.

Koh Bak Kiang, who was initially sentenced to 25 years' jail and 24 strokes of the cane after he pleaded guilty to two charges of heroin trafficking and a count of drug consumption, saw his jail term cut to 13 years with 24 strokes of the cane.

On Thursday, he pleaded guilty to two lesser charges of trafficking in a Class A controlled drug other than heroin at a High Court hearing, after Chief Justice Sundaresh Menon granted the prosecution's application to set aside Koh's convictions for heroin trafficking.

With the usual one-third remission for good behaviour, Koh will be released in two months.

He was arrested in April 2007 for transporting 45 packets of powdery substances containing 14.99g of heroin from Serangoon Central to Katong Plaza. He also delivered a brown envelope containing 14.99g of heroin to a tattoo shop in Katong Plaza.

Koh knew that he was trafficking a drug belonging to the Class A list of controlled substances, but did not know the exact drug he was transporting.

Class A drugs are considered the most harmful and addictive drugs, and attract the most severe punishments, including the death penalty.

At his home, anti-narcotics officers also found a bag containing 20.7g of ketamine.

At a hearing in November 2007, Koh, a former engineer with a master's in business administration, pleaded guilty to his charges. In his mitigation plea during sentencing, he stated that he did not know the drug he was trafficking was heroin.

Trafficking above 15g of heroin carries the death penalty.

To be convicted for trafficking a specific drug under the law, an offender has to know the actual drug trafficked.

Koh appealed against his sentence shortly after, but this was dismissed in April 2008.

Then in April 2014, he made an application for a late appeal against his conviction.

The application was heard by CJ Menon last July. He sent the case to the State Courts, to consider the admission of additional evidence. The case was heard there in June this year.

On Thursday, at the High Court hearing before CJ Menon, the prosecution asked for Koh's heroin trafficking charges to be set aside, and for them to be replaced with the lesser trafficking ones.

Meting out the new sentence, CJ Menon told Koh: "You will be released shortly, in a matter of a few months."

After Koh thanked him, the judge said: "When you are released, please don't do this again."

Koh's mother and two brothers were in court.