As part of multilateral response to the pandemic, G20 leaders also committed to continue working together to facilitate worldwide trade and coordinate responses in ways that avoid unnecessary interference with global traffic and trade, according to the statement.
Group members are gravely concerned about the risks posed to all countries, but especially developing and underdeveloped nations - whose healthcare systems are not as able to take on the challenge of Covid-19 - and refugees.
"We must have an effective and coordinated response to this pandemic", the king said.
Saudi Arabia, the current G20 chair, called the video summit amid earlier criticism of the group's slow response to the disease.
Showing more unity than at any time since the 2008-2009 financial crisis that led to the G20's creation, the leaders said they committed during a videoconference summit to implement and fund all necessary health measures needed to stop the virus' spread.
Brazil is a G20 country, as is Saudi Arabia, which is now in the group's presidency and slated to host the G20 Summit next October.
Some member countries have announced economic stimulus packages to offset broad suspensions of air travel and shutdowns of many businesses.
The U.S. Chamber of Commerce urged G20 leaders to match a pledge by countries like Australia and Canada to keep supply chains open and avoid export controls. Leaders call on organizations to make concerted efforts, including involving the private sector, to provide social, economic and healthcare support to emerging countries.
The videoconference scheduled for 1200 GMT also risks complications from an oil price war between two members, Saudi Arabia and Russian Federation, and rising tensions between two others, the United States and China, over the origin of the virus.
In preparatory talks, China and the United States agreed to call a timeout on their coronavirus blame game, the South China Morning Post reported, citing diplomatic sources.
"The U.S. -China dynamic is pivotal to successful G20 coordination, never more so than now as countries grapple 24/7 to confront and contain a pandemic we do not yet fully understand", former acting U.S. Trade Representative Miriam Sapiro said.
Meanwhile, though the Kremlin said oil markets were not under discussion by the G20, Washington could still try to launch a debate about ending a price war between Moscow and Riyadh that has pushed crude prices to near 20-year lows as the pandemic destroyed global demand.