The assembly has opposed key changes ministers want to make to the South East Plan - a 20 year planning framework for the region - in a report to Government.
It said the minimum figure had no ceiling, which could have a negative accumulative affect on the area by stretching existing resources and have an additional impact on the environment.
Chairman councillor Paul Carter said: "There is a clear mismatch between Government's housing ambitions and their lack of commitment to invest in the south east.
"Without investment in roads, transport, health services, schools, sewerage and water supplies to support new homes we will see a decline in quality of life for both new and existing residents."
The assembly also raised concerns about the economic problems with the Government's changes to the plan. Mr Carter said: "It is unrealistic to increase our annual housebuilding target to a minimum of 33,000 homes a year in the current economic climate.
"A minimum target means we can't plan effectively for the land and infrastructure we need - but when developers won't build homes because they can't sell them it calls the whole task into question."
For the original planning targets the Assembly had consulted experts on the impact to the environment and the infrastructure which would be needed.
Mr Carter said: "Ministers need to listen to the region as we know what is achievable within the current funding and environmental constraints, but they must also be prepared to fund the necessary infrastructure to ensure that existing homes as well as new homes are catered for. We need a reality check on housing delivery during the economic crisis."
Government consultation on its proposed changes closes on Friday and the Secretary of State has the final decision on the plan, which is expected to be announced in the winter.