The High Court denied the leave application by Prabagaran Srivijayan, 29, and K Datchinamurthy, 32, to initiate the legal challenge.

According to the duo’s lawyer, N Surendran, Justice Hanipah Farikullah ruled, in chambers, that the courts had no powers to interfere with foreign policy issues.

Prabagaran and Datchinamurthy filed judicial reviews separately, seeking to compel the government to start legal proceedings against Singapore at the International Court of Justice (ICJ) for denying them fair trials.

They also wanted a declaration from the court that the government was obliged to protect their lives and freedom.

Both named the foreign minister and the Malaysian government as respondents in their judicial reviews.

Surendran said they would be appealing against the decision.

“We think it is wrong and are disappointed with it.

“This is related to the treatment of our fellow countrymen abroad,” he added.

Umar Saifuddin Jaafar and Awang Armadajaya Awang Mahmud represented the foreign minister and the government, while Andrew Khoo held a watching brief for the Malaysian Bar.

Both Prabagaran and Datchinamurthy were found guilty in Singapore of trafficking in diamorphine, a pure form of heroine, in 2012 and 2015, respectively.

Both have petitioned for clemency from the Singapore president but have not got any response yet.

They are currently awaiting execution in a Singapore prison.