Following a second amendment to the Civil Contingencies Bill in two weeks, bodies such as local authorities, NHS trusts and utility companies must take account of the role that voluntary groups can play in responding to major incidents.
The Government said the change would create a "climate of expectation" that charities would be consulted and involved where appropriate.
The change came about following a concerted lobbying campaign by a coalition of four charities - the Red Cross, St John Ambulance, WRVS and the Salvation Army.
Virginia Beardshaw, director of UK services at the Red Cross, said the Government's decision had vindicated the stand the charities had taken.
They had continued to lobby even after the House of Commons had thrown out the amendment in May.
"We were right," she said. "What this amendment does is entirely consistent with the thrust of government policy for the voluntary sector and that logic prevailed. This is our business. We respond to emergencies 24 hours a day, 365 days a year."
Baroness Buscombe, the Conservative shadow spokeswoman for Culture, Media and Sport in the House of Lords, lauded the charities' "tenacious approach to the Bill".
The concession on responding to emergencies followed another last week (Third Sector, 10 November), in which the Government extended to the voluntary sector the requirement for local authorities to give advice to organisations about how to survive disasters.