Afghan peace negotiators on Tuesday welcomed the release of eight Taliban prisoners who had been held in Pakistan, hailing the move as a significant boost to efforts to end 11 years of war.

The High Peace Council, set up to conduct negotiations with the Taliban, said the releases underlined that neighbouring Pakistan was supporting talks as US-led NATO combat troops withdraw from Afghanistan.

Support from Pakistan, which backed the 1996-2001 Taliban regime, is seen as crucial to peace in Afghanistan after NATO's departure.

Former Taliban justice minister Nooruddin Turabi was among the eight freed on Monday, adding to 18 others released in November after appeals from Kabul.

Afghan officials believe Taliban leaders released from Pakistani jails could help bring militants to the negotiating table.

"It is a practical step in the right direction," said Ismail Qasimyar, head of international relations for the peace council.

"It shows the Pakistani authorities have opened a new chapter for positive cooperation with Afghanistan.

"Pakistan can play an important role in bringing peace to Afghanistan. We welcome this move and hope those freed will become peace messengers," he told AFP.

But analysts say the freed men have little influence over current Taliban leaders and doubt whether they will even encourage them to open peace talks.

The Taliban refuse to talk directly with the Afghan government of President Hamid Karzai, which it regards as a "puppet administration" of the United States.

The most senior Taliban figure detained in Pakistan, former deputy leader Abdul Ghani Baradar, has also not yet been released.

"So far none of those released have done anything significant," said Waheed Mujda, a former civil servant in the Taliban government.

"Turabi was an important individual when they were in power but by the time he was taken prisoner about two years ago he wasn't. We don't know what these men will be able to do for the process."

Mujda added that Turabi, who was a Taliban military commander and a deputy to supreme leader Mullah Omar, was believed to be seriously unwell.

Pakistan-based analyst Rahimullah Yusufzai was also sceptical about the impact of the releases.

"These people have no authority as they have already been replaced by others," he warned.

"They will not even go to Taliban-held areas, they may even prefer to stay in Pakistan."

Pakistan issued a statement saying eight detainees, including Turabi and Abdul Bari, the governor of Helmand province during the hardline Taliban regime, had been set free. Their current location was not known.

Foreign ministry spokesman in Islamabad Moazzam Ahmad Khan said the move would "further facilitate the Afghan reconciliation process" after Pakistan in November released 18 Taliban prisoners on the request of the Afghan Peace Council.

Taliban spokesman Zabihullah Mujahid confirmed the release of Turabi and three others, rather than the eight men cited by Pakistan.

"Four of our friends, including Mullah Turabi, have been freed. They will join their families shortly," he told AFP.

The Taliban were ousted by a US-led invasion in 2001 and there are concerns that a civil war could erupt if Afghanistan's army and police are unable to impose stability after NATO's withdrawal.