A self-styled "Global Business Coalition" of industry groups has urged the Group of 20 leading economies to counter threats to global free trade.

U.S. President Donald Trump is taking a more aggressive, protectionist posture on trade than his recent predecessors that has sparked retaliatory measures from the European Union, Mexico and Canada.

The business coalition urged G20 finance ministers to renew their commitment to free markets at a meeting this weekend in Buenos Aires.

"We are deeply concerned about the stability of the rules-based global trading system," the coalition said in a statement seen by Reuters.

"To create wealth, the business world needs reliable, modern, international rules, predictability and stability as well as strong, impartial referees," the coalition added.

Trump earlier this month warned the World Trade Organization that "we'll be doing something" if the United States is not treated properly, after the EU said that U.S. automotive tariffs would hurt its own vehicle industry and prompt retaliation.