Moody's Investors Service released its quarterly report on Tuesday. The agency expects G20 GDP to rise 2.7% this year, increasing to around 3% in 2016, compared to 2.9% in 2014. Moody's added that 2015-16 growth forecasts "are still below the G20's average growth rate before the financial crisis".

According to the report, the downward risks for 2015-2016 forecasts are "correction in Chinese equity and property prices, a disorderly response to the US Federal Reserve's anticipated policy tightening and a Greek exit from the euro area".

Moody's forecast the Chinese economy to grow 6.8% this year and 6.5% in 2016.

The U.S. economy is expected to expand 2.4% in 2015 and 2.8% in 2016.

Eurozone's economy is expected to grow 1.5% in both 2015 and 2016.

Moody's forecasts the Brent oil price to average $57 a barrel in 2016, higher than the 2015 average of $55.