Russia readied for a grandiose Red Square military parade Saturday to mark 70 years since the victory over Nazi Germany in World War II, but Western leaders were going to stay away due to the Ukraine crisis.

New tanks, mammoth nuclear missile systems and some 16,000 troops were set to sweep past the Kremlin under the gaze of President Vladimir Putin in a defiant show of strength held in front of leaders from countries including China, Cuba, Zimbabwe and Venezuela.

Huge crowds of Russians were expected to flood into central Moscow to take in the largest such parade since the collapse of the Soviet Union from 10 am (0700 GMT) aimed at whipping up patriotic zeal and commemorating the country's vast war-time sacrifices.

But the Kremlin showcase is being overshadowed by the current crisis over Ukraine, which has seen ties between Russia and the West plunge to their lowest point since the Cold War over Moscow's seizure of Crimea and allegations Putin is fuelling a brutal separatist conflict.

United States President Barack Obama has snubbed the event, as have the leaders of Russia's other key World War II allies Britain and France, which is sending its foreign minister instead.

German Chancellor Angela Merkel has ducked out of attending the parade but will fly to Moscow Sunday to lay a wreath at the grave of the Unknown Soldier and meet with Putin.

Instead, most prominent on the podium next to Putin will be United Nations chief Ban Ki-moon, Chinese leader Xi Jinping, and India's President Pranab Mukherjee.

Egyptian leader Abdel Fattah al-Sisi, Cuban supremo Raul Castro, Venezuela's Nicolas Maduro, Zimbabwe's Robert Mugabe and South Africa's Jacob Zuma are also set to attend the event.

The list of attendees and absentees reflects the Kremlin's hunt for new allies in the face of tough Western sanctions over Ukraine -- although North Korea's reclusive leader Kim Jong-Un eventually decided to reject an invitation to show up.

- March of remembrance -

An estimated 27 million of the former Soviet Union's soldiers and civilians were killed in WWII and the Red Army's triumph in the deadliest war in history is seen as a huge point of pride in Russia, with ubiquitous black and orange ribbons marking the event around the country.

Over 70 percent of Russians say a close family member was killed or went missing during the war, making Victory Day an emotional symbol of unity for the nation.

Some 165,000 people are expected to march through central Moscow after the parade with portraits of relatives who fought in the war.

In recent years the victory in the 1941-1945 conflict, known in Russia as the Great Patriotic War, has been raised to cult status and critics accuse Putin of seeking to co-opt the country's history to boost his personal power.

The Kremlin has also used WWII narratives to rally support for its current agenda, for example painting the Ukrainian government as Nazi sympathisers.

This year the parade will see over a hundred military planes -- including long-range nuclear bombers -- swoop over Moscow in a spectacular fly-by.

Also on show for the first time will be some of the Russian military's latest weaponry designed to replace creaking Soviet-era equipment.

One of the most prominent is the latest generation Armata tanks, which represent a key part of the major overhaul of Moscow's armoury.

Smaller parades in 25 other cities will involve a total of another 25,000 soldiers and even nuclear submarines, according to the defence ministry.

Russia's leadership have shrugged off the no-show by Western leaders and insisted nothing will rain on the victory parade, with even the weather not being left up to chance.

Early Saturday, planes will seed rain clouds with chemicals such as silver iodide in a bid to prevent them bursting over central Moscow during the morning parade.