The Law Society fears a review of the Family Court could result in cases that need its expertise being transferred to other courts.
The cost of the Family Court has risen by two thirds since 2005 and is now more than $137 million per year.
The Government says the review is about finding efficiency and controlling expenditure, not cutting services.
But the Law Society says it fears matters needing the specialist attention of the Family Court could be moved to other jurisdictions.
It is worried that access to the Family Court may also be severely restricted.
The Society says that although the review is timely, it is also a kneejerk reaction to budget constraints.
In addition, Auckland barrister Catriona MacLennan says the review is a waste of money - as two comprehensive reports on the Family Court since 1993, have been ignored.
Otago University's dean of law Mark Henaghan also says any changes aimed at dismantling the special role the Family Court plays, would be wrong.
Costs should not be the focus - society
The Law Society says the review should not focus on the rising costs of the court.
Family law section deputy chair Caroline Hannan said when the figures are broken down, there are a number of costs that are not to do with the court's processes, such as the rental costs of buildings.
This year marks three decades since the Family Court's inception. In 2010 it dealt with 68,500 new applications.
In Hamilton the waiting time is 36 weeks, in Auckland it is 30 weeks and in Wellington 26 weeks.