The difficult economic climate should not stop world governments from working to end poverty, says the international director of Micah Challenge.
Joel Edwards was among the 79 religious leaders to sign an open letter on Friday reminding government leaders that there are 1,000 days left to meet the Millennium Development Goals to halve extreme global poverty.
The MDGs were agreed by 182 nations in 2000, committing them to halve hunger, introduce education for all children, provide clean water and sanitation for millions, tackle diseases like malaria, and greatly improve maternal health.
Signatories of the letter included the Archbishop of Canterbury, the Most Reverend Justin Welby.
The letter highlights the work that still needs to be done if the MDGs are to be realised by the 2015 deadline.
While maternal mortality is falling by 1% per annum, this rate is below the 5% annual improvement needed, while hunger remains a daily reality for some 868 million people, the letter states.
Mr Edwards said: "Meeting the MDGs is possible. Even in hard times we should not waiver from our promise to the poorest people in the world. If we tackle waste and corruption, we could free up billions, more than enough to meet the MDGs."
The publication of the letter was accompanied by a social networking campaign in which people were invited to tweet their support using the hashtag #1000DaysToGo.
Dr Charles Reed, foreign policy adviser to the Church of England said, "Eight years ago, all the G8 leaders made commitments on aid. But despite some progress, we are still $19 billion short in our giving."