The parliament was poised to adopt a bill on Friday that would legalise trials before military courts for another two years, a measure human rights activists say negates the basic principles of justice and denies those on trial the chance for a fair defence.

Prime Minister Nawaz Sharif's government was expected to fast-track the draft before lawmakers amid indications that the National Assembly would unanimously back the constitutional amendment. The proposed amendment authorises the military to try any suspect on terrorism-related charges.

A similar amendment was adopted in 2015, allowing military courts to carry out trials of militant suspects under a two-year mandate, which expired in January.

That measure came after a December 2014 Taliban attack at APS school in Peshawar, which killed 154 people, mostly children. The assault also prompted Pakistan to lift its moratorium on the death penalty. Since then, over 400 convicts have been executed, though most were not linked to terrorism-related cases.

Along with the military trials, the forces have also carried out several military operations against militants in lawless tribal regions bordering Afghanistan, including a major push that began in mid-2014 in North Waziristan, a militant base.

Militants in Pakistan have killed tens of thousands of people over the years, seeking to overthrow the government and install their own harsh brand of Islamic law.

Last month, authorities expanded the powers of the paramilitary Rangers to include the eastern Punjab. Previously, the force could only pursue and arrest suspects in Sindh and Baluchistan, as well as in the northwest.

Rights groups have consistently criticised the military courts, which had a total of 274 cases referred to them over the past two years. During that time, the courts sentenced 161 people to death.

"They don't meet the internationally accepted principles of justice. These courts don't give the suspects the right to select a lawyer," Zohra Yusuf, who heads the independent Human Rights Commission of Pakistan, told The Associated Press.

The trials are conducted by army officers — not lawyers — who lack proper legal background and experience, she said. The trials are held behind closed doors and suspects' families often learn about the rulings against their kin through the media.

Instead of relying on military courts to be the judge, jury and executioner, Yusuf appealed for authorities to reform the country's judicial system.