"To prevent them from doing harm we must take all measures, including stripping supporters of the terrorist organisation of their citizenship," Erdogan said in a speech in Ankara, referring to the outlawed Kurdistan Workers Party (PKK).
"These people don't deserve to be our citizens. We are not obliged to carry anyone engaged in the betrayal of their state and their people."
Erdogan has refused to give any quarter to the PKK which has been blamed for a string of attacks in Turkey in recent weeks after the collapse last year of a truce in its decades-long fight for greater autonomy and rights for Kurds.
In March, Erdogan came under fire for calling for the definition of terrorism to be expanded to include journalists, activists and others who "exploit their positions, pens and titles and put them at terrorists' disposal."
But this was the first time he has proposed that supporters of the PKK be stripped of their nationality.
"Supporters (of terror) who pose as academics, spies who identify themselves as journalists, an activist disguised as a politician ... are no different from the terrorists who throw bombs," Erdogan added Tuesday.
"But like a wolf in sheep's clothing, they serve the same purpose as the members of the terror organisation. As a nation we need to be careful. No-one must commit treachery against the state and the nation behind our backs."
Erdogan has also pushed for lawmakers from a pro-Kurdish party to be stripped of their parliamentary immunity so they can be prosecuted for "terrorist propaganda".
As part of a growing crackdown on free speech, several Turkish lawyers, journalists and academics have been arrested for criticising the military's heavy-handed tactics in Kurdish-dominated towns and cities in the southeast.
