CAF, which lobbied for the introduction of payroll giving in 1987 and runs payroll giving schemes, said the review failed to provide a clear way forward. About 650,000 employees currently donate £89m a year through their company payrolls, but many people think the figure has the potential to be much higher.
The institute hired consultancy Strategy Complete, led by Vanessa Potter, former director of policy and external relations at the Big Lottery Fund, and researcher Dr Jonathan Scales, to review the scheme and consider ways of increasing take-up. Consultation on its proposals ended last Friday.
In a statement, CAF described the recommendations as "a missed opportunity" and "broad, undeveloped and untested". It said: "A lack of in-depth engagement with donors led to gaps and flaws in the analysis.
John Low, chief executive of CAF, said: "What was promised as a root-and-branch review has not given us the full picture."
Megan Pacey, director of policy and campaigns at the institute, said: "Because CAF has such an enormous interest in payroll giving, there is a degree to which you would expect it to say these things. The recommendations would put it in a position of vulnerability and force it to change."
Mark Astarita, director of fundraising at the British Red Cross and chair of the institute's policy advisory board, described the review as "one of the most practical and useful pieces of work that I've ever had the pleasure to see in the area of general policy around fundraising".
But Peter O'Hara, managing director of Workplace Giving UK, said: "There should have been more research on what employers think, because they're the driving force in taking the scheme forward."
Bill Lane, chief executive of South West Charitable Giving, said some proposals had merit but others were unworkable.
Take steps towards making the scheme compulsory in organisations where it is requested by staff
Find ways of helping payroll donors when they move jobs
Review the statutory framework for payroll giving agencies
Review the role and management of payroll giving agencies.