British tabloid The Sun reported that Putin would quit the presidency early next year because, it claimed, he has Parkinson's disease, as evidenced by him appearing to shake weirdly in a recent video.

The Kremlin's spokesperson, Dmitry Peskov, rejected such claims and attested that Putin is in excellent health.

"This is complete nonsense. Everything is fine with the president," Peskov said in comments carried by state news agency TASS.

The rumour emerged as lawmakers introduced draft legislation to Russia's lower house of parliament on Thursday to reinforce Putin's immunity against prosecution after his presidency.

"The president of the Russian Federation retains immunity upon terminating his authority," the text says.

"He cannot be held criminally or administratively liable and cannot be detained, arrested or subjected to a search or an interrogation."

Putin, 68, has been in power as president or prime minister for two decades. He is the longest-serving Russian or Soviet leader since Joseph Stalin.

Australian Associated Press