By Belinda Goldsmith

UNITED NATIONS (Thomson Reuters Foundation) - As world leaders brandish a hard-fought new set of global goals designed to improve lives in all countries, the question of who foots the trillion-dollar bill remained open on Saturday as financial pledges started rolling in.

The United Nation's 193 member countries on Friday adopted 17 Sustainable Development Goals (SDGs) as a roadmap to end poverty and hunger, fight inequality and conquer climate change over the next 15 years, or 800 weeks.

The goals tackling issues in both rich and poor countries replace an earlier U.N. action plan, the Millennium Development Goals, which focused mainly on poverty in developing nations.

While aid funds and debt relief were key for the millennium goals, there is wide recognition of the need for other sources for the estimated $3 trillion a year needed to enact the SDGs.

The World Bank, with other development banks, coined the phrase "Billions to Trillions" to illustrate the challenge.

Organisation for Economic Cooperation and Development (OECD) Secretary-General Angel Gurria said private sector participation was critical while governments need to strengthen tax and regulatory systems to encourage investment.

"Without the private sector, it is not going to happen, as we have budgetary constraints in every country," Gurria told the Thomson Reuters Foundation in an interview.

"You'll have a lot of pledges but you'll need a framework to allow the flows (of finance) to then happen naturally."

A July conference in Addis Ababa addressing SDG funding issues made clear that private sector as well as philanthropic foundations had a major role to play, with private enterprise the main source of economic growth and job creation, outsizing donor nation funds.

Meanwhile the world's richest nations again committed to a target of earmarking 0.7 percent of gross national income for overseas development assistance - although few meet that level in practice - which now stands at about $135 billion a year.

Pledges of funding started to roll in during the U.N. three-day SDG summit that ends on Sunday.

U.N. Secretary-General Ban Ki-moon announced more than $25 billion in initial commitments over five years from 40 countries and more than 100 international organizations to help end preventable deaths of women, children and adolescents.

Contributions to boost funding for gender equality powerment included $5 million from Chinese e-commerce giant the Alibaba Group and $1 million from the Bill & Melinda Gates Foundation.

Chinese President Xi Jinping unveiled an initial pledge of $2 billion with aims to increase that to $12 billion by 2030.

Helen Clark, administrator of the United Nations Development Programme, said the agenda would not be achieved without business - and that meant ensuring stability and good governance in countries to support big partnerships.

"Business is attracted to where there is a solid and able environment and basic rule of law, commercial law, dispute resolution, peaceful and inclusive societies," said Clark, the former New Zealand prime minister.

"For us, it's fundamentally not about financial contributions that business makes to U.N. agencies. It's about shared values ... the way business does business. Is it inclusive, and is it sustainable?"

Centerpiece to funding talks has been a focus on helping countries boost their domestic resources by improving tax collection and attacking tax evasion and illicit cash flows.

While some criticize this as tinkering with a broken global tax system, Gurria said SDG funding does not need new initiatives but can build on and improve existing structures.

He called for a team of "tax inspectors without borders" to build trust in countries' systems and boost investment.

"If you get it right, you can get trillions," Gurria said.

But it is agreed that funding alone was not enough to achieve the global goals, with policy changes needed to support the priorities.

Michael Green, executive director of the Social Progress Imperative which analyzes countries' progress on social measures, said economic growth alone would not meet the SDGs, which deal with subjects ranging from energy subsidies to developing genebanks.

"The SDGs are about political will and inclusion," Green told the Thomson Reuters Foundation. "We have the resources if we use them properly for this is not just about money."

(Additional reporting by Michelle Nichols, Editing by Ellen Wulfhorst.; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, corruption and climate change. Visit www.trust.org)