Tax avoidance by big firms sparked protests in London earlier this year
Thursday's meeting of G20 nations is expected to sign an agreement to fight tax avoidance by multinationals.
The group of developing and developed nations formally backed plans to tackle international tax avoidance and evasion at its meeting in July.
The gathering, in the Russian city of St Petersburg, is officially about global economic matters.
However, the most meaty topic of conversation is likely to be Syria and how to handle the crisis there.
The meeting, between representatives of the countries that account for two-thirds of the world's population, will also ponder the effects of an end to the US financial stimulus programme.
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The BBC's Stephanie Flanders explains how the fictitious "Big Bizz Co" avoids high tax bills
One of the main topics to emerge this year has been multinational companies' use of legal, highly complex tax minimisation systems.
Oxfam warned this week that such behaviour was not only harmful to the countries in which companies were based, but paid little or no tax, but was also damaging to developing nations, with African countries losing 2% of national income to tax-dodging by businesses.
The G20 became an important platform for global policy discussions in 2008 when it was effectively re-booted to co-ordinate a global response - involving developing as well as the developed G7 nations - to fighting the financial crisis.
ConcernsThe meeting takes place as the leading economies of the eurozone and the US show signs of increasing growth.
End QuoteShould the Fed refrain from "tapering" its cheap cash injections, even as the US economy is recovering, in order to keep cheap money flowing into emerging markets?”
That in itself though means that policymakers, particularly in the US, are planning to edge away from the lax monetary policies brought into alleviate the effects of the credit crunch.
Some observers are concerned that investors are not ready to deal with an end to easy money and rock bottom interest rates, and this is also lined up as a key topic for discussion.
Growth in developing economies has slowed sharply and many countries' currencies have lost value against the US dollar, which has strengthened in anticipation of firmer interest rates.
However, crisis-ridden Syria is the most immediate global concern to many.
The two most important nations - the host country, Russia and the US - disagree deeply over how to respond, and comments on the situation in and around that country are likely to attract the most attention.
The issue of gay rights is another non-economic subject on which Russia and the US hold opposing views, and that issue is also expected to be raised on the sidelines of the meeting with any comments expected to be closely scrutinised.
Source: BBC News - Business http://www.bbc.co.uk/news/business-23966218#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa
