In a statement issued from her Geneva office, Pillay said laws being passed in Moscow on freedom of assembly, of speech and of information would have a detrimental impact on human rights.
"I urge the government of the Russian Federation to avoid taking further steps backwards to a more restrictive era," she declared, in a clear reference to the more than seven decades of communist rule, which collapsed in 1991.
Her statement left no doubt that she saw the flurry of recent legislation, which Russian rights groups say presages a wider crackdown, as being linked to the return to the presidency in May of Putin, a former official in the Soviet KGB.
"In just two months, we have seen a worrying shift in the legislative environment governing the enjoyment of the freedoms of assembly, association, speech and information in the Russian Federation," Pillay said.
Her statement was issued as Russia's upper house of parliament approved a law tightening government control of civil rights groups, while branding those who get foreign funding "foreign agents" - a term many Russians associate with spies.
Russia has brushed aside criticism of the bill from the United States and other Western countries, and ignored complaints from its own human rights organisations.
But as a member of the United Nations' 47-member Human Rights Council it will be stung by censure from Pillay, a former high court judge in South Africa who has been outspoken on rights in many countries, including the United States.
She and her office - which is independent of the Council -have been fiercely critical of the way Russia's ally Syria has handled unrest, as well as of US ally Israel for its treatment of Palestinians.
The one-time International Criminal Court judge – who diplomats say was blocked this year by the United States from getting a second four-year term - has also spoken out on perceived rights violations in China, Iran, Pakistan and Sudan.
With a final two-year mandate, she has just returned from visits to former Soviet Central Asian republics Kyrgyzstan and Kazakhstan, where she openly spoke of failings by their governments in protecting and promoting human rights.
On a recent visit to the Maldives, thousands of demonstrators paraded through the capital demanding her arrest and execution after she criticised the island state's laws which compel every citizen to be a Muslim.
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