"Our greatest defence against Covid-19 is solidarity and cooperation," the UN chief was speaking at a virtual summit of G20 leaders under the theme "Building an inclusive, sustainable and resilient future," where he highlighted the importance of G20 leadership in the fight against the pandemic and the effort to build back better, Xinhua news agency reported.

First of all, the Secretary-General said that the G20 leadership is critical in "halting the further spread of the pandemic."

"Yesterday, I was encouraged by the broad recognition that vaccines - as well as tests and treatments - must be global public goods, available and affordable for all," he said, referring to the progress in the first-day meeting of the summit.

"But I want to repeat the call on G20 members to support the ACT-Accelerator and its COVAX facility. There is a financial gap of 28 billion US dollars and we need 4.2 billion dollars of that immediately for mass manufacturing, procurement and distribution around the world," he said.

The top UN official also said, the leadership is also vital in mobilizing the resources to build forward better.

"There will be no different and better future without stronger action now to provide the necessary liquidity and tackle the debt emergency of the most vulnerable," he explained.

"It means strengthening the firepower of the IMF (International Monetary Fund) and other international financial institutions in support of the developing world, including through a new issuance of Special Drawing Rights and the reallocation of unused SDRs," Guterres added.

It means broadening the eligibility of the G20 debt initiatives to all vulnerable developing countries, including the middle-income ones that need it, he said.

The UN chief believed that the third important role of the G20 leadership is aligning their recovery efforts with the 2030 Agenda for Sustainable Development and the Paris Agreement on Climate Change.

To build an inclusive, resilient and sustainable post-COVID world, public spending must be linked with achieving the Sustainable Development Goals, said the Secretary-General.

"We have a moral obligation to ensure that the trillions of dollars for Covid-19 recovery - money that we are borrowing from future generations - does not leave them burdened by a mountain of debt on a broken planet," he said.

"The recovery must help to reconcile humankind and nature on all fronts. From climate to biodiversity, from protecting the oceans to stopping deforestation and land degradation," he added.