Central banks from major economies stand ready to take steps to stabilize financial markets by providing liquidity and preventing a credit squeeze if the outcome of Greek elections on Sunday causes tumultuous trading, G20 officials told Reuters.

A senior U.S. official cautioned that the Greek election will not provide "the definitive signal on what happens next" in the euro zone debt crisis.

But if severe market strains emerge after an unusual confluence of three elections this weekend - there are important polls in Egypt and France as well - central bankers are on standby to ensure enough cash is flowing through the financial system.

"The central banks are preparing for coordinated action to provide liquidity," said a senior G20 aide familiar with discussions among international financial diplomats. His statement was confirmed by several other G20 officials.