The NCVO is offering support to the Voluntary Arts Network, the Central Council of Physical Recreation and Heritage Link, and is asking culture secretary Tessa Jowell to discuss how charities will be affected.
Jowell announced that third sector bodies would be protected from the Big Lottery Fund's extra £425m Olympic contribution. The money will come from its grants to statutory agencies.
"There is no doubt that this could have been much worse," said Pete Moorey, parliamentary and campaigns officer at the NCVO. "But our campaign does not end here. People need to be held to account."
Jowell's announcement was hailed as a partial victory by voluntary sector umbrella groups. Ed Miliband, minister for the third sector, said: "Amid extremely tight funding pressures, I am pleased that it was possible to protect the voluntary sector's funding from the Big Lottery Fund."
But Arts Council England, the Heritage Lottery Fund, Sport England and their affiliated bodies reacted with dismay and criticism (see below).
Shadow charities minister Greg Clark said the BLF decision was cold comfort.
"The fact that it could have been worse will not reassure the charities that are going to suffer," he said.
Sir Clive Booth, chair of the BLF, said the fund would still be contributing "more than its fair share" to the Olympics. Funding after 2009 would inevitably be reduced, he added.
Kevin Curley, chief executive of Navca, said stopping the transfer of any additional money from lottery distributors would have been "mission impossible".
"We set out to stop the transfer of money that would otherwise go to local voluntary and community services," Curley said. "That is what we have achieved."
Ben Wittenberg, head of policy and research at the Directory of Social Change, said: "It is a short-term win. It only secures the funding that is already committed."
- See Editorial, page 15.