The Archbishop of Canterbury who leads the Anglican church, and charities such as Christian Aid have appealed to the UK government not to cut billions from Britain's international development budget.
Archbishop Justin Welby told the Observer newspaper that lives had been "genuinely" changed by Britain's overseas aid, Christian Today reported.
At the same time Christian Aid joined a number of other Christian charities in an open letter to Prime Minister Boris Johnson in light of the COVID-19 crisis.
The cut is an adjustment to a decimal point that has a huge impact on aid.
The UK Treasury was criticized after it became known that cuts of more than 4 billion British pounds ($5.33 billion) were being planned.
The Treasury wants to cut the aid budget from 0.7 percent of gross national income to 0.5 percent next year and plans to make the announcement as part of next Monday's one-year spending review, The Guardian newspaper reported.
The aid budget was £15bn last year. A reduction to a 0.5 percent target in 2021 would result in billions more cut, but the precise amount would depend on overall growth.
The Conservative Party-led government had in its manifesto pledged to commit 0.7% of gross national income to aid spending each year.
Welby said it was important that Britain stood by poorer nations in "tough times as well as the good".
"I've seen the good done by UK aid around the world," Welby told the newspaper.
"A global recovery from the economic consequences of the pandemic requires a global response. Keeping our aid commitment is a strong signal that the UK is a reliable partner for long-term economic, social, environmental and educational advancement across the globe."
Numerous aid agencies, including Christian Aid, Tearfund and CAFOD urged the Prime Minister not to go ahead with the plans.
"When 115 million people look set to be pushed back into extreme poverty, now is the time for an international, collaborative response to Covid-19," they said in their open letter to Johnson.
"It is a time that requires increased, not decreased, engagement from the British government in its efforts to make the world healthier, safer and more prosperous."
They said, "Our world is in the thick of a crisis like no other; our families, our society, our economy are being challenged in previously unimaginable ways.
"Thankfully, this country has a resource which is used to stepping up, supporting and finding solutions.
"This resource is the Church: a body of people who know all about compassionately supporting people in their communities and inspiring others to do the same."
They said that alongside the churches work a "myriad of Christian charities who exist to equip and support the Church as they look after those around them.
Right now, in the most difficult of times, we are doing what Jesus told us to do: to love our neighbor."