Tariffs, tech and taxes will strain finance ministers from G20 countries at a meeting in Argentina next week overshadowed by the gathering clouds of a trade war, reports AFP from Buenos Aires.

The two-day meeting in Buenos Aires, which starts Monday, comes at a particularly tense moment just two days before the United States is set to begin imposing tariffs on steel and aluminum imports.

US President Donald Trump has pledged to impose 25 per cent duties on imported steel and 10 per cent on aluminum. Only neighbors Canada and Mexico were exempted.

"Up to now, finance ministers were reticent to tackle the subject of trade, considering that it was not their area of competence," a source close to the negotiations said.

"But the situation is such today that they will not be able to not speak about it. The question is how far we can go."

Meanwhile, the US treasury wants to use the meeting to win consensus on how to combat China's trade practices, particularly its cheap steel exports.

Except that Trump, far from being reserved when it comes to Beijing, also regularly attacks Europe.