The third sector should develop more "transparent, simple and collaborative" structures to help it influence government at a regional level, according to a new report.
The study from think tank IPPR North says that front-line voluntary organisations and generic and specialist sector infrastructure bodies all try to engage with public agencies regionally, which fragments the sector's message.
It argues that large, individual organisations should work more closely with generic infrastructure bodies to coordinate activity, and join forces to pay for policy officers.
IPPR's recommendations follow an interim report published in February, which found that 60 per cent of charity leaders thought the sector's voice at regional and sub-regional level was "not very well established".
The final report, All Inclusive? Third Sector Involvement in Regional and Sub-regional Policymaking, was published last week. It says researchers found a widespread perception in the public sector that the third sector did not have a coherent voice.
Public sector interviewees said the private sector was more adept at developing consensus over key issues and charging representative bodies, such as the CBI, with delivering messages.
Jenny Berry, director of Acevo North, which helped with the study, said: "The third sector must be fit for the future in order to engage effectively and thrive. This is the time for the sector to begin a new conversation about how we can achieve a well-established voice at the table."
The report says central government should send a "clear signal" to the public sector that it is expected to engage with the third sector. It also recommends the introduction of a statutory duty for public sector bodies to involve stakeholders, including charities.
Berry said this would "strengthen the sector's hand at a regional level".