Prominent rights activists said passage of the bill would catapult Russia's justice system back to the times of Stalin's purges.
"It returns the Russian justice to the times of 1920-1950s," the activists said in a statement, urging lawmakers to oppose what they described as the "legislation in the spirit of Stalin and Hitler."
The activists included the head of the Moscow Helsinki Group, Lyudmila Alexeyeva, and the head of Civic Assistance, Svetlana Gannushkina.
Despite the criticism, the draft is likely to receive a quick approval by parliament, which is dominated by Kremlin loyalists.
The government systematically rolled back Russia's post-Soviet political freedoms during Putin's eight-year presidential tenure - and shows no signs of stopping.
The current law defines state treason as actions harming external security by passing information to foreign parties.
But Putin's proposed bill broadens the term "treason" to include inaction as well as action, includes a breach to internal security and adds international organizations to foreign ones as those forbidden to receive state secrets.
Critics also warned the loose wording will give authorities ample leeway to prosecute those who cooperate with international rights groups.
Some Russian commentators said the government wants the new law in place quickly to curb possible protests resulting from the global financial crisis.
In a related move, the upper house of Russia's parliament passed a bill Wednesday that would end jury trials for those facing charges of terrorism and treason.
The Kremlin-controlled Federation Council approved the bill 147-0 with two abstentions. It must be signed by President Dmitry Medvedev to take effect.
The bill strips defendants charged with some crimes - involvement in illegal armed units, violent seizures of power, armed rebellion and mass riots - of the right to jury trials. Instead they would face judges.
The bill's authors say the change was necessary because they claim juries have acquitted many suspects despite strong incriminating evidence. Critics denounced the bill as another blow to democratic principles.