Lawyers who submit "last-minute applications" after the appeal process has been completed will now have to explain why they could not raise the arguments during the appeal.
The apex court made this clear last week when it dismissed the applications of four death-row prisoners who challenged key provisions of the Misuse of Drugs Act, saying they were not constitutional.
The Court of Appeal, comprising Chief Justice Sundaresh Menon and Judges of Appeal Chao Hick Tin and Andrew Phang, noted the applications are the "latest in a string" from many offenders who were convicted of capital drug offences but unable to satisfy the prescribed requirements under Section 33B of the Act.
If they satisfy the section's conditions, the court has the discretion to sentence them to life imprisonment.
The latest ruling follows a Court of Appeal rejection last month of the 11th-hour challenges by drug traffickers Chijioke Stephen Obioha and Devendran Supramaniam to their death sentences. Their separate applications were heard a day before their executions.
The applications of the four offenders centred largely on two key points:
•One, whether it was constitutional for the Public Prosecutor to certify the accused person had substantively helped the authorities to disrupt drug trafficking activities.
•Two, whether the Public Prosecutor's decision can be challenged on grounds of bad faith or with malice, or on other grounds as well.
The four are represented by a team of lawyers led by Mr Eugene Thuraisingam. They also want the court to review the constitutionality of the Act's provisions on punishments.
They argued, among other things, that the provisions were not - under the Constitution - a valid law that can deprive them of their lives.
They want the apex court to issue an order to substitute the death sentence with life imprisonment or that they be re-sentenced after a stay of execution.
All four had been assessed by the Public Prosecutor to have not substantively helped the Central Narcotics Bureau as stated in the Act.
Deputy Public Prosecutor Francis Ng, in contesting their claims, urged the appeal court to "be slow in exercising its discretion to reopen its previous decisions", among other things.
In giving its decision, the court said the claims of three of the prisoners could have been raised in their earlier appeals "which they failed to do" as there was nothing "new".
It also reiterated that "no court in the world would allow an applicant to prolong matters ad infinitum through the filing of multiple applications", a comment it made in an earlier case involving executed murderer Kho Jabing, who killed a constuction worker while robbing him.
"We take exception to such a drip-feeding approach which clearly squanders valuable judicial time," Judge of Appeal Chao wrote on behalf of the court.
The court noted that one applicant, D. Nagaenthran, had sought a separate judicial review last year of the Public Prosecutor's decision not to certify that he substantively assisted the authorities.
The case was still pending and the apex court said it was premature for it to consider the issue of the Public Prosecutor's decision.
The validity of the relevant section made no difference to his sentence at this stage, Judge of Appeal Chao wrote.
Lawyers like Mr Sunil Sudheesan said the court's move is a signal reminder that counsel are officers of the court and not bound to the client pushing for the delay.
Mr Sunil suggested that "a practical alternative'' would be to let the lawyer explain in the application why it was not raised during the appeal, rather than requiring him to give the explanation in a separate affidavit as will be the case now.