The International Monetary Fund has called on some G20 nations to boost government spending amid weak global growth and increasing risk.

In a report issued ahead of the G20 meeting in China, the IMF said growth could be even lower if the current increases in economic and political uncertainty in the wake of the 'Brexit' vote continue. The IMF has lowered its forecasts for global growth by 0.1 percent to 3.1 percent this year and 3.5 percent next year.

It wants advanced economies like Germany and the United States to channel more public spending on infrastructure to help boost global growth, an issue that has sparked divisions among G20 members.