Russian oligarchs are preparing to buy swathes of ultra-expensive property in London to protect their wealth against the country's crumbling economy, Britain's Daily Mail online newspaper reported on Thursday.

The paper said that in the past few days six buyers have contacted luxury London agents Beauchamp Estates to ask for £100 million homes in upmarket Mayfair, Belgravia and Kensington in order to get their money out of Russia.

In the past week Beauchamp has also seen a 10 per cent spike in requests from Russian buyers as panic about an economic collapse spread with the rouble's plunge against the US dollar.

The new wave of investors will further tighten Russia's grip on London's super-prime market, as they already buy one in five of the capital's most expensive properties, said the Mail.

Two days after the first Western sanctions against Russia came into effect in April, Penthouse D in One Hyde Park in the posh Knightsbridge area was bought for £140 million by an Eastern European, sparking speculation it was a Russian trying to secure their cash, the Mail added.