GENEVA - The world's 20 most advanced economies, the G20, erected 20 new trade restrictions between October and May, covering trade worth $335.9 billion, the World Trade Organization said on Monday, warning that several more were being considered.

However, G20 economies also implemented 29 measures to reduce trade barriers during the period, covering $397.2 billion, it said in a regular monitoring report. But new barriers were rising at a far faster rate than the historical average, the WTO said.

(Reporting by Tom Miles; editing by Stephanie Nebehay) ((tom.miles@thomsonreuters.com; +41 58 306 2006; Reuters Messaging: tom.miles.reuters.com@reuters.net))