Comey, sacked by the Trump administration last month, acted like US whistleblower Edward Snowden, said the Russian leader during an annual televised call-in known as "Direct Line with Vladimir Putin", Xinhua news agency reported.
"When a special service head records a conversation with the commander-in-chief and gives it to the media through one of his friends... he is then not a special service head but a human rights advocate who defends a certain position," said Putin.
Snowden, a computer professional who had done contractual work for the US National Security Agency, is now living under asylum in Russia. He fled to Russia in 2013 after revealing thousands of classified documents to the press.
"If there is persecution against Comey, we will be ready to grant him political asylum as well," said Putin.
According to the Trump administration, Comey was fired because of his handling of the Hillary Clinton email investigation during the 2016 US presidential elections.
As for Comey's investigation into Russian interference in the presidential elections, Putin said Comey provided no evidence.