Ian Johnston, chief executive of the British Association of Social Workers, and Doug Nicholls, general secretary of the Community and Youth Workers' Union, both said the constant restructuring of local authorities was taking its toll on the children's and youth sector.
"We know local authorities spend too much time restructuring, which has consequences for frontline services," Johnston said. "We have restructured too often and not allowed things to settle properly."
Nicholls added: "Everyone in youth services is constantly being reorganised and the unitary authority reorganisation is just another layer."
The government announced last week that the council structure in Cheshire, which currently has six district and one county council, would be replaced by two unitary authorities.
Similarly Bedfordshire, which currently has two county and three district councils, will be served by two unitary authorities from April next year - a decision opposed by Bedfordshire County Council, which has taken the matter to judicial review. The council has been calling for one single unitary authority for Bedfordshire instead of two.
The new arrangements will save more than £16m a year in Cheshire and £18m in Bedfordshire, which can be used for frontline services or to cut council tax, local government minister John Healey claimed.
But Nicholls said: "It's not clear whether there will be cuts but we need to ensure development towards unitary status is built on improved funding."
Caroline Abrahams, programme director for children's services at the Local Government Association, said: "With this instability it's important that authorities keep a focus on delivering children's services."
