CAF said the new fund would offer grants of up to £10,000 to groups including charities and social enterprises with incomes of less than £1m.
It said in a statement that, although the fund was worth an initial £5m, it expected further contributions to be added.
CAF said the fund was open to registered charities, community groups, social enterprises and other organisations with charitable purposes.
It said it aimed for grants to be paid to successful organisations within 14 days of application.
“Unfortunately, we anticipate that there will be a large number of eligible organisations which we cannot fund,” guidance published by CAF said.
“There are a number of other Covid-19 response funds being established throughout the UK for various purposes, and we will endeavour to signpost to other funds where possible.”
Sir John Low, chief executive of CAF, said the situation for some charities was “dire”.
He said: “Some of the charities and small organisations we rely on are facing very difficult times. They are telling us they face financial difficulties, with fundraising events cancelled or postponed and volunteers rightly staying at home.
“These are the people who are delivering support in so many ways in every corner of the UK and we need them to be there during and after this crisis.”
For more information and to apply, click here.