Police said a portion of the building, Ruby Residency, located in the Chawdi ward of Canacona, collapsed burying labourers working at the site.
While nine labourers are injured, more than 20 are feared trapped in the debris. Over 300 army jawans, police and other state agencies continued the rescue work, which lasted through the night.
More than 20 are feared trapped in the debris.
Chief Minister Manohar Parrikar who was monitoring the rescue operations until late Saturday said: "An FIR has been filed against the builder, contractor and the municipal engineer in-charge. We will not spare anyone."
The construction was being carried out by a Navi Mumbai-based real estate development firm, Bharat Developers and Realtors Pvt. Ltd.
The building is a part of a partially completed residential complex where actress Asha Parekh, sports minister and local MLA Ramesh Tawadkar own flats.