The latest meeting, in the Italian seaside city of Bari, comes ahead of a G7 summit meeting May 26-27 in Sicily, and follows on last month's meeting of the group's foreign ministers.
Treasury Secretary Steven Mnuchin said his meetings with world finance leaders have helped ease their concerns that the United States is moving to hard-edged protectionist trade policies.
Mnuchin said his meetings with finance leaders had led to better understanding of the US president's position that trade must be fair and balanced as well as open.
But he said the continued uncertainty about the direction of United States policy represented a risk, echoing comments made on Friday by Japanese Finance Minister Taro Aso.
In a final statement, the ministers said, "we reiterate our commitment to global economic and financial cooperation and we remain determined to use all policy tools - monetary, fiscal and structural - individually and collectively to achieve our goal of strong, sustainable, balanced and inclusive growth".
The US is adamantly challenging the status quo in worldwide trade, and as a result, the most recent G7 meeting produced an indecisive communique, indicating the rising degree of uncertainty, possibly bearing the seeds of trade wars and greater currency manipulations in the global struggle for competitiveness.
Finance ministers from the G7 club of rich countries committed to greater coordination in facing the rising threat of global cyberattacks in a joint statement Saturday. That divergence augurs for potential disagreements when the nations' leaders gather in Sicily later this month - an event which marks Trump's first major worldwide summit as U.S. President.
Finance chiefs from some of the world's richest nations began a two-day meeting in Italy on Friday, with Europe, Japan and Canada hoping to come away with a clearer picture of U.S. President Donald Trump's plans on important policies.
"Excessive inequality, also at the global level, undermines confidence and limits future growth potential", it said, vowing to use all policy tools - monetary, fiscal and structural - individually and collectively to achieve our goal of strong, sustainable, balanced and inclusive growth".
The aim of the treaty is "helping countries collect what we believe is a fair share", Gurria told The Associated Press on Friday on the sidelines of a meeting of finance officials from the Group of Seven advanced economies.
Earlier, he told reporters that "the relationship with Mnuchin improves every time we see each other".
Many G-7 countries had been particularly concerned about the USA rolling out a border tax that could choke exports to the country.
Mr Mnuchin said the opening-up of the market for beef sales to China was a "huge deal" for the administration and for United States farmers.
The G20's reference to trade said only that they were "working to strengthen the contribution of trade to our economies".
He said the Trump administration's economic policies aren't directly aimed at pursuing policies that would restrict trade, but rather are meant to spur US growth and aid the global economy.
"The emphasis was initially on a border tax, which is taxation, but also trade policy", said Italian Finance Minister Pier Carlo Padoan in an interview.