Several former Taliban commanders and the brother of former Taliban defense minister Mullah Ubaidullah were among the escaped convicts who disappeared without detection late Friday from a prison in Kandahar, said Yousaf Pashtoon, the governor of Kandahar.
"This is a very serious incident," he said, adding that a province-wide search has been launched for the prisoners.
Kandahar was the stronghold of Afghanistan's former hardline Muslim Taliban regime.
Two government officials who spoke on condition of anonymity said five prison officials were also missing and are believed to have helped the Taliban, who had been arrested in recent months during fighting between Afghan forces and insurgents.
"There was no sign of any resistance," one of them said.
Pashtoon also confirmed that five prison officials were missing and said their role was being investigated.
The government officials said prison authorities realized there had been a jailbreak only when they saw the empty cells on Saturday.
"The Taliban dug a 30-foot (9-meter) tunnel and initial investigations indicate that they were working on it for the past month," Pashtoon said.
He said 41 of the 54 Taliban detained at the prison had escaped. He did not say why the remaining insurgents did not break out.
The Taliban regime was ousted by a U.S.-led military operation in Afghanistan in late 2001.