The outer-south regional director of Connections, Kimberley Flanagan, said families would miss out on help as State Government funding failed to keep pace with Casey's population growth and the economic crisis started to bite.

She said the agency's funding model had not changed since the area was "just cows and paddocks" and did not take into account the soaring number of families in the municipality.

The agency's Burremah school in Narre Warren closed in December due to a lack of State Government funding.

The school, set up in 1974, helped up to 16 students with behavioural difficulties each year.

Ms Flanagan said it cost Connections at least $136,050 a year to run the school and it received up to $80,000 in annual state funding - meaning up to a $56,000 deficit for 2008-09.

Facing a $50,000 funding cut in 2009, the not-for-profit organisation asked for extra funding to save the school, but its requests were refused.

Ms Flanagan said funding for the agency's other services in Cranbourne, Narre Warren, Dandenong and Pakenham was also under strain.

Ms Flanagan said the Government's funding model was based on population studies conducted in 2000, but funding levels for the family support service were unchanged despite Casey's soaring population growth.

"In Cranbourne, we are not getting the same level of services as in areas of no population growth or shrinking populations."

Between August 2008 and January 2009, the number of families seeking help at Connections increased from 133 a month to 181.

"We find that we can't respond to the demand and have had to tighten our eligibility criteria [for helping clients]," Ms Flanagan said.

"We have greater demand but we can't see more people."