The developers of the HM Revenue & Customs (HMRC) site in Goring have submitted a planning application to Worthing Borough Council.
The document seeks permission to build 296 homes on the Barrington Road site, and was submitted to the council on December 30 last year.
It comes after a public exhibition of the plans was held in November last year.
The application, brought forward by development managers Cannon Capital Developments on behalf of Mapeley, the current owners, is for 147 houses and up to 163 apartments or retirement flats. There is also provision for a 68-bedroom care home and 160 square metres of space that could be used for shops or restaurants.
HMRC will vacate the site in March, 2021, to move to its new premises at the redeveloped Teville Gate House in Worthing.
The new five-storey development is being constructed and has replaced the derelict building that used to house the tax office.
It will become home to around 900 full-time-equivalent employees from existing offices.
Worthing will be one of five specialist sites located across the UK, as part of a ten-year plan to go from 170 offices to 13 regional centres, five specialist sites, eight transitional sites and a London head office.