The local authority asked them to make 4 per cent savings by the end of the financial year in response to a 12 per cent reduction in its own funding from central government.
The council said if organisations were unable to make savings, it would consider each case on its individual merits.
Organisations that receive less than £10,000 a year of council funding will be exempt from the exercise and will not be subject to any enforced cuts during this financial year.
Rafiq Chohan, the council’s assistant director for economic development and inclusion, attended a meeting with voluntary sector groups on Monday to discuss the situation.
"The voluntary sector has understood the challenges and is working with us to deliver better efficiency," he said.
"One of our priorities is finding out what they feel they need against the available resources," he said. "We will have to consider the needs of each individual organisation."
Ramesh Kukar, chief officer of Slough Council for Voluntary Service, praised the council for protecting smaller groups, but said the timing would make it difficult for some.
"The good thing about it will be that those organisations that get less than £10,000 will not be asked to make cuts," he said.
"But it will be difficult because we are half the way through the year, so anyone who has not been thinking about it until now will feel an 8 per cent impact, not a 4 per cent impact.
"Also, if a group is relying heavily on the council, it’s going to be hard. What we are hoping is that the council will look at specific groups."
Slough CVS will be running workshops to help those affected.