Christian Aid, which usually launches appeals only in response to emergencies, has started a fundraising campaign for £1.5m to enable it to implement its existing plans for the next financial year.
The international development charity is launching what it calls an "unprecedented" appeal in a bid to raise the money by 19 February so it can carry out its planned work for 2010/11.
Unfavourable exchange rates in the past year have increased the cost of funding some overseas projects by as much as 20 per cent, according to the charity.
Paul Valentin, international director at Christian Aid, said that without extra funds "some very difficult decisions" would have to be made before the new financial year began.
"Many of the people we work with in developing countries were already trying to survive on $1 a day before the financial crisis hit," he said. "Any increase, however small, in food and fuel prices means they may be unable to afford the basics and need our support more than ever."
The charity has also earmarked 80 posts for redundancy as part of plans to make £6m of savings over the next two years, although it is not yet clear how many compulsory redundancies will be made. Some of the positions are already vacant as a result of an organisation-wide recruitment freeze.
Last month, Christian Aid announced that Loretta Minghella, chief executive of the Financial Services Compensation Scheme, would take over from Daleep Mukarji as its director in April.