The warning follows the release of a government consultation on the draft regulations for neighbourhood planning.
Under the Localism Bill, local planning authorities will be able to designate community and business groups as neighbourhood forums that can draw up neighbourhood plans for development, subject to a referendum.
The draft regulations propose that a referendum could be tied in with another election up to six months either side of when the referendum was originally due to be held.
Tony Burton, director of Civic Voice, which supports civic societies in England, said this period is too long. "It would not be good to unduly delay a referendum as a lot of the momentum behind neighbourhood planning could be lost," he said.
The government also revealed that it does not intend to set a limit on how long a council has to decide whether to designate a forum. But community groups would have six weeks from when they inform the council which area they want to comprise the neighbourhood they will focus on to come forward with proposals to set up a forum.
But Burton said that having no time limit for councils could allow those that are less keen on neighbourhood planning to "obstruct the process".
The government says in the consultation that it wants to have a light touch approach to neighbourhood planning and will leave it to councils to agree the process.
The consultation is available via PlanningResource.co.uk/go/referencesection.