The introduction of Compact Plus is merely "reinventing the wheel" and will only create confusion among voluntary organisations, according to the NCVO.
The umbrella body said the primary aim of the new Compact Commissioner should be to raise awareness of the existing Compact and how to implement it, not to promote a new initiative.
Yet another initiative would only confuse voluntary bodies and could be unnecessary because a summary of each code is already available, it claimed.
"It is not necessary to reinvent the wheel," said Campbell Robb, director of public policy at the NCVO.
The umbrella body also said that ensuring organisations know the Compact exists was not enough. "We don't just want promotion, but awareness too," said Saskia Daggett, compact advocacy manager at the NCVO. "People have heard about the Compact, but they don't know how to use it. We welcome time and resources coming from the Home Office, but we also want research to find out where to go with it."
But the Home Office insisted there was a need for the new scheme. "We do publish summaries of the codes, but there is still a need to address the issue of clarity," said a spokesman for the Home Office. "Compact Plus will be an additional opt-in scheme rather than a replacement for the Compact. It will increase choice."
He added: "The Compact Commissioner is there to ensure that the gap between aspirations and reality does not exist."
Daggett said that, for the Compact to work, voluntary organisations would have to make more effort to use it. "We advise people to read it and see it as a living document, not just for fundraising relationships, but for all relations with government," she said. "It is often criticised for having no teeth, but voluntary bodies are the teeth."