Rugby Council for Voluntary Service, Nuneaton and Bedworth CVS, Warwick District CVS and Rugby Volunteer Centre merged this week to form Warwickshire Community and Voluntary Action, which will be known as Warwickshire Cava.
But Stratford CVS has decided not to take part because it believes the finances are not right. North Warwickshire CVS has delayed its involvement because it has to balance its books. It will join in 2009.
John Jackson, chair of Stratford CVS, said he supported the concept of one merged organisation but it would need to be financially sound.
"In our opinion, under the present arrangements the new organisation will not be able to balance its books without dipping into the reserves," he said.
Stephen Nightingale, project manager for the merger and chief officer for Warwick District CVS, said: "In my view we are doing the right thing. Certainly, the trustees of the four merging organisations believe that this is the right solution for Warwickshire."
Under the plans, the posts held by Nightingale and Liz Stuart, chief executive of Nuneaton and Bedworth CVS, will be made redundant. Paul Tolley, chief officer of Rugby CVS, has been appointed chief executive of Cava.