The Group of 20 countries will start their leaders' summit meeting in Italy on Saturday to discuss issues such as climate change and energy.
The two-day summit will be the first face-to-face meeting in two years. Security is tight in areas near the venue in Rome, with car traffic restricted and many police officers deployed.
Italy, which will chair the meeting, aims to have the member countries reach a certain degree of consensus on the target year for net zero emissions of greenhouse gases.
Italy hopes this will give momentum to discussions at the COP26 climate conference, which is scheduled to start in Britain just after the G20 summit.
In Rome, leaders are expected to discuss preventive measures against the spread of the coronavirus, including supplying vaccines equally to developing countries.
They will also likely discuss the impact of soaring energy prices and the disruption of supply chains on the global economy, as well as responses to these problems.
It's believed the leaders will confirm the introduction of new tax rules for global companies, already agreed at ministerial level.
Attention is focused on whether the G20 members will be able to agree on those issues and send a positive message to the international community.