UN Secretary-General Antonio Guterres has asked the Group of 20 (G20) leaders to promote equitable growth.

"I encourage G20 members to take the lead in implementing policies that promote not only rapid and robust, but also equitable growth," said Guterres in a letter to G20 leaders dated June 20, which was made public on Wednesday.

The UN chief himself will attend the G20 summit in Osaka, Japan, on Friday and Saturday and will meet bilaterally with world leaders.

Equitable growth means to ensure that those living in the "rust belts" of the world are not left behind, including through social protection, and better leveraging new technologies, he wrote.

It also includes shaping an international financial system that is fit for the purpose of achieving sustainable development for all. And with a rules-based multilateral trading system in crisis, G20 countries must take the lead in advancing the necessary reforms of the World Trade Organization, he said.

Inclusive growth needs to empower communities and provide equal pay and employment opportunities and decent work for women, he said.

Equitable growth also implies less economic volatility, given the sharp human costs associated with economic crises, he said in the letter. "G20 countries, thus, should lead efforts to strengthen the global financial safety net and increase its resilience to systemic risks. I call on G20 countries to undertake the regulatory and other policy changes that will make our financial systems sustainable and facilitate the mobilization of longer-term investments on which sustainable development depends."

Guterres also asked the G20 leaders to increase the flow of public and private finance toward investments that are aligned with the Sustainable Development Goals, in part by shaping incentives so that private capital flows toward sustainable development.

He stressed the need to seize the opportunities of the digital revolution, which is advancing rapidly, with great promises for increased efficiency, and with already profound impacts on economies and societies.

But digital divides can also grow rapidly, and the rules of the game -- from data to taxation -- that will shape opportunities need to be designed in an inclusive manner, said Guterres.

He invited the G20 leaders to a UN climate summit in New York in September 2019.

"By participating at the highest political level and bringing concrete actions to the table, G20 members can help lead us on the path to achieve our shared goal of a safe and prosperous future for people and the planet," said Guterres.

"By acting collectively and with urgency to manage global risks, we can pave the way to achieving our vision for the future. The G20 must play a central role. A role that can drive real change ... I urge you to lead the way in ensuring that no one is left behind."