The government says the law is needed to fight resurgent Kurdish separatists who have stepped up attacks in the past two years after calling off their unilateral cease-fire.
The new law will delay guaranteed access to a lawyer for the first 24 hours of detention and expand the definition of acts classified as crimes of terrorism.
Critics say the law would make it a crime simply to espouse views shared by rebel groups or even to publish a statement by an illegal organisation.
Critics also say the anti-terrorism law gives too much leeway to conservative nationalists who dominate Turkey's judiciary and who see their main task as defending their view of the state.
The European Union, which began accession talks with Turkey in October, has expressed concern over the legislation.
"The anti-terrorism bill does not restrict press freedom and freedom of expression," state news agency Anatolian quoted Cemil Cicek, the country's justice minister as saying.
The last two years have seen a resurgence of rebel attacks, particularly by the Kurdistan Workers Party (PKK). The attacks had, in fact, subsided after the capture of the group's leader, Abdullah Ocalan, in 1999.
The outlawed rebel group, considered a terrorist organisation by Ankara, the United States and the EU, launched a campaign in 1984 for an ethnic homeland in the country's predominantly Kurdish southeast.