The unit wants to help them combine to share HR managers, buy services from larger organisations with spare capacity or buy them from consortia.
It will run pilot schemes in the autumn, helping councils for voluntary service in Birmingham, Rotherham and Derby to provide HR services to charities. The councils will get small grants.
Gareth Coles, information officer at the unit, said: "Small organisations tend to deal with human resources issues only when they become a problem. Then they start having to pay legal fees to find that expertise."