Abdullah Ocalan, jailed leader of the militant group known by its Kurdish initials, PKK, called on fighters to leave the country as part of a truce with the government.
Senior PKK member Cemil Bayik, however, said honoring the terms of the deal needed legal backing.
"Without legal assurances, there can be no withdrawal," he was quoted by Turkish news agency Today's Zaman as saying.
Bayik said similar efforts at peace in the 1990s ended when Turkish forces attacked militants seeking to suspend operations.
Turkish Prime Minister Recep Tayyip Erdogan told the ruling Justice and Development Party that such legal guarantees from Parliament weren't expected. The Turkish government said the National Intelligence Organization will oversee the PKK withdrawal.
"Some parties say Parliament should pass a law for the safe withdrawal of the PKK terrorists but no such step will be taken," Deputy Prime Minister Bulent Arinc confirmed.
The PKK began its military campaign against the Turkish government in the 1980s. It operates from the Turkish border with Iraq and Iran. Ocalan was captured in the 1990s.