The project was due to start this month but funding issues involving the Scottish Government and the European Union are likely to lead to delays.
At a special meeting of education committee on Tuesday, members decided they would proceed to financial close on the Dalbeattie Learning Campus.
Councillors approved all project-related transactions, development of technical design, market testing, financial modelling and cost predictions.
The vision for the £24.459 million Dalbeattie Learning Campus is to create a flexible, modern, inclusive and sustainable campus for the community of Dalbeattie which will support attainment, achievement and participation for our children and young people and also provide wider access for the whole community.
The campus has been designed so that the main halls, teaching spaces and sports facilities will be available to community groups, clubs and organisations, enabling the asset to be used far beyond school core hours.
In addition to the proposed new schools, the project will include a range of sports facilities, community learning facilities and space for visiting services.
Chairman of the education xommittee, Councillor Jeff Leaver, said: “The council has now fulfilled our obligations and we are ready to start the construction of this exciting project.
“The ball is now very much in the Scottish Government’s court. We hope they will be able to resolve their funding issues as quickly as possible to ensure we are still on target for the successful completion on time of this ambitious project for the people Dalbeattie. The local community deserves nothing less.”