Fourteen voluntary sector organisations, including the Stroke Association, Sue Ryder Care and Leonard Cheshire, have joined Acevo's full-cost recovery campaign coalition.
The coalition aims to hold the Government to its four-year-old commitment to ensure statutory funders adopt full-cost recovery in contracts with voluntary organisations by next month.
According to a survey, 97 per cent of Acevo members think the Government will not hit the deadline, but the campaign aims to keep the pressure on.
"We want the campaign to drive home the importance of the issue," said David Hunter, policy and development officer at Acevo.
"Full-cost recovery is standard practice across both the public and private sectors - if you told someone working on a bid or project that their overhead costs weren't going to be met, you'd be greeted with incredulity.
We want to end this anomaly."
Others backing the campaign include Groundwork, YouthNet and Amicus.