South Ayrshire Council has appointed the firm to develop council offices at the Riverside Block, which will act as the first part of the site’s wider development.
Morgan Sindall will be supported by architect Keppie Design, which delivered original designs for the offices.
Ayr Renaissance submitted a masterplan for a mixed development between High Street and the River Ayr last year.
This includes office accommodation and housing, as well as shops, cafes, restaurants and public spaces.
Demolition of the existing site now well advanced and Morgan Sindall will start on site in spring 2018.