Federal Interior Minister Chaudhry Nisar Ali Khan confirmed the execution of Shafqat Hussain would be delayed by 30 days.
Shafqat Hussain’s case has attracted international attention as his lawyers and family claim he was only 15 at the time of the killing.
Nisar Ali Khan said a committee would be set up to try to determine Hussain’s true age.
“We have not received any proof from anybody about his age, all the fuss is being made in the media,” the Minister told reporters.
“We have to ensure justice not only for Shafqat but for the boy who was brutally killed and his body dumped in a Karachi river.”
Shafqat Hussain, convicted of killing a seven-year-old boy in Karachi in 2004, was just hours away from the gallows when an initial delay was ordered last Wednesday.
Shafqat Hussain was arrested and during his first interrogation admitted kidnapping and killing Umair, whose body was found in a plastic bag in a stream.
Shafqat Hussain later withdrew his confession, saying he had made it under duress, but the case came before an anti-terrorism court which sentenced him to death.
Shafqat Hussain had been due to face the noose on January 14 but the government halted the execution amid protests about his age, and ordered an investigation.
An anti-terrorism court in Karachi last week ordered that Shafqat Hussain, convicted of killing, be hanged on March 19.
Shafqat Hussain’s case has triggered outrage from rights campaigners, who complain he did not get a fair trial and was only 15 at the time of the killing.
Reintroducing the death penalty was part of Pakistan’s move to step up the fight against militants since a Taliban massacre at a school in Peshawar in December.