A group of politicians, academics and human rights campaigners have signed an open letter attacking Russia's record on democracy and political freedom.
They claim official ceremonies to be held in Moscow undermine the memory
of those who fought and died in the war.
Signatories include ex-Czech President Vaclav Havel and former US ambassadors.
In the letter, to be published in full in the UK's Financial Times newspaper to coincide with the Moscow ceremonies on 9 May, signatories accuse modern Russia of betraying the principles behind victory in 1945.
They write: "[We] believe the venue and hosting of this event are altogether unsuited to the fundamental principles for which that historic victory... was achieved."
Russia in 2005 lacks strong democratic institutions, while political freedoms, civil liberties and the rule of law are weak, the signatories allege.
"It seems to us a mockery of the occasion to gather there in honour of the 20th century's climactic sacrifice for Europe's freedom."
As well as Mr Havel, the letter's 75 signatories include former prime ministers of Estonia and Bulgaria and academics and democracy activists from eastern and western Europe and the US.
Several current and former members of the European parliament, US congress
and UK parliament also signed the letter.
Richard Allen, former national security adviser to former US President Ronald Reagan, has signed, alongside several former ambassadors.
Pro-democracy campaigners drafted the letter as concern about Russia grows in Europe and the US.
President Putin recently described the break-up of the Soviet Union in 1991 as a "geopolitical catastrophe".
The Russian leader has been accused of concentrating too much power in the hands of the Kremlin, and US Secretary of State Condoleezza Rice recently criticised levels of media freedom in Russia.
Neighbours Latvia and Georgia have accused Russia of aggressive behaviour. Last year the Kremlin explicitly favoured pro-Moscow candidate Viktor Yanukovych in Ukraine's disputed presidential election.
Bruce Pitcairn Jackson, president of the Project on Transitional Democracies, which drafted the letter, said there was a wide dissatisfaction with events in Russia.
"Human rights, political prisoners, show trials and aggressive negotiations with neighbours are important contradictions to our values and ideas," he said.