Australia’s stock market plunged on opening Monday, losing $20 billion within an hour.

The S&P/ASX 200 and the All Ordinaries indices both fell over 2.4 percent within the first 20 minutes of trade, and several major banks, including Commonwealth Bank, Westpac and National Australia Bank all saw over 2 percent losses. 

Uncertainty in global stock markets, fueled by ongoing volatility in China and political uncertainty in Greece, have battered markets across the world.

The losses continued after the initial dip. As of 12:33 a.m. EDT, the ASX 200 was trading down 3.36 percent at 5,050 points, while the All Ordinaries was down 3.25 percent to trade at 5,045 points.

IG Group markets analyst Angus Nicholson told the Herald Sun that the session was one of the market’s worst in five years, but said he was still hopeful. “I don’t think it will last through the week,” he said.

The Australian slide also comes amid drastic losses on Wall Street, where the major Dow Jones index fell 531 points Friday, its biggest in a year.

Australian Treasurer Joe Hockey said that though markets would remain volatile for a while, the global economy’s fundamentals remained fairly strong. He warned that the volatility would continue for a while, especially with the U.S. Federal Reserve’s plans to raise interest rates in September.

“If they do increase their interest rates, then you will see movement of money from equity markets, probably into bond markets,” he said.