The former Archbishop of Canterbury Dr Williams is among the faith leaders calling on the Chancellor to cancel the debts of developing countries battling the impact of coronavirus.
He is one of 77 Christian, Jewish, Muslim and other faith leaders to sign an open letter to the Chancellor ahead of a meeting of G20 finance ministers this weekend.
The threat to developing countries is "clear and shocking", they said, as they warned that millions more people are at risk of falling into extreme poverty as a result of the pandemic.
The faith leaders estimate up to 270 million people face hunger by the end of 2020 and that 340 million are threatened by unemployment.
In April, G20 finance ministers agreed to suspend bilaterial debt payments but the letter urges them to completely cancel debt payments owed by developing countries in the years 2020 and 2021.
The faith leaders said such a step would make it possible for the most vulnerable communities to withstand the challenges of the pandemic.
"This is a critical and rapid means of ensuring that health workers in developing countries have the best chance of helping to defeat the coronavirus and that countries have the resources at hand to build back from the economic devastation the pandemic has wreaked – including by assisting communities already being hit by the effects of the climate crisis," the letter reads.
"To insist on debt repayment in the face of the suffering caused by this pandemic would be an affront to the faith traditions that we represent.
"Indeed, there is an overarching moral case for debt relief in many faiths."
They added: "We urge you to show the ambition and leadership needed to meet this challenge."
The letter has been signed by Church of England bishops, the head of the Evangelical Alliance Gavin Calver, as well as Methodist, United Reformed, Baptist, New Wine, Redeemed Christian Church of God and Salvation Army leaders. The representatives of Christian NGOs SCIAF, CAFOD, Tearfund and Christian Aid have also signed the letter.