Proposed cuts in Rugby Football Union funding and changes to National League structures have caused clubs to be concerned about their futures.
The proposed cuts would see money given to clubs for insurance and travel to away games drop significantly.
National Clubs Association chairman Sir Hal Miller said: "Clubs are trying to arrange sponsorships and talk to investors, so it's an anxious time."
The RFU's Terry Burwell said it was likely league funding could change.
On the subject of funding for clubs playing in the National Two and Three leagues, Burwell told BBC London 94.9: "The likelihood is that the change in finance will actually align them closer to the community game rather than the elite game."
Burwell did move to reassure clubs that neither the Premiership, nor any other league, would become ring-fenced.
"There's a firm commitment to promotion and relegation being part of the structure and nothing that's being proposed is likely to change that," he said.
On Saturday, 6 September the RFU is holding a meeting with clubs called the 'Rugby Landscape Forum' to discuss the findings of an online survey which asked the clubs their opinions on the future structure of rugby in England.
Miller will attend the meeting and has sought to reassure the clubs he represents.
"The Union seem to think that it's probably better to get the pain out the way in one hit and obviously that's a much more traumatic decision"
"The actual facts are that none of these proposals are yet adopted by the RFU as policy."
Chairman of the RFU, Martyn Thomas, recently told a newspaper that as many as five teams could be relegated at the end of the 08/09 season from National League One, with only one club promoted from National Two, reducing National One to just 12 teams.
Chairman of First Division Rugby Geoff Cooke said: "In an ideal world I think it would be best phased over two years to lessen the impact on clubs, and not just the clubs in National League One but the clubs below that.
"The Union seem to think that it's probably better to get the pain out the way in one hit and obviously that's a much more traumatic decision.
"At the end of the day it's the RFU that have got the power, they can determine the structure, they'd like to do that with the support of the clubs; they've just finished a lengthy war with the Premiership clubs and I'm sure they don't want an ongoing war with the clubs in the National Leagues."
BBC London 94.9's rugby union show "The Scrum" will have more on this story on Thursday, 4 September at 2100 BST.
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