The government has announced £120m of match funding for appeals run by UK development charities over the next three years.
Justine Greening, the international development secretary, announced the UK Aid Match programme on Saturday.
In order to be eligible for funding, charities must be UK-based, working in one of 26 "priority countries" and running a specific appeal that is expected to raise at least £100,000.
The Department for International Development said in a statement that charities must also have a plan to make sure that at least 400,000 people have the chance to hear about their appeal.
There will be two funding rounds in each of the three years that the programme will operate.
Charities will need to apply by 1 November for appeals that will run between March and September 2014, the first round of the programme. The second round will open in March.
Spending will be limited to £40m in each of the next three years, a DfID spokeswoman said.
The DfID statement said that at least £1m per funding round will be ring-fenced for charities with an annual income of less than £1m.
A pilot of the scheme ran between summer 2011 and spring 2013, during which the government matched a total of £42m in public donations to 17 different charities, from an estimated 3.8m people in the UK. About six million of the poorest people in the developing world were expected to benefit from the pilot programme, the spokeswoman said.
Greening said: "Aid Match matters for people donating to charities because it means we take the overseas development priorities of the public and make them ours too.
"People power is literally doubling the amount that great causes are receiving from the public. And when individual donors know about our match-funding scheme, they tend to give more because they recognise that each pound they give doubles up."