Each of the nine English regions has a generalist network and a black and minority ethnic network, all representing the voluntary sector, but the networks fear for their futures if funding is not renewed in March.
The Regional and Voluntary Community Sector Networks, which represent the nine general networks, wrote to third sector minister Kevin Brennan last week about future funding.
"One of the OTS's aims is to engage with as much of the sector as possible, and we reach 140,000 groups," said Elizabeth Balgobin, chief executive of LVSC, the London network.
She said the grants helped networks attract other sources of funding and losing them might mean closure for some.
Voice4Change England, the body that represents the BME networks, has also called for the grant to be renewed (Third Sector Online, 10 November).
An OTS spokesman said the latest grant was only ever intended to last for three years.