Trade ministers from the G20 nations have called on their governments to roll back anti-trade measures that have become more pervasive than any time since 2009.

Following a two-day meeting in Shanghai, the ministers said in a joint statement on Sunday that they were "concerned" about rising protectionism around the world and "significantly slowed" trade growth figures. They backed a set of nine core principles for global investment policymaking ahead of the September G20 summit in Hangzhou.

The ministers also said they recognized that excess steel capacity is a global issue that requires "collective response" and pointed to government support of producers that have led to "market distortions."

China, among other producers, has been accused by the U.S. and U.K. of dumping cheap steel and driving down global prices.