Antrim and Newtownabbey Borough Council is facing a £15.6m shortfall in its budget this financial year due to the coronavirus pandemic.
The council made the announcement as it confirmed moves to furlough half of its staff as a result of restrictions forcing the closure of all of its buildings and outdoor sports areas.
This has resulted in a loss of income of around £665,000 per month - an estimated £8m in the current financial year.
In addition, the council said its rates income will be slashed by around £7.6m, resulting in a total estimated shortfall of £15.6m in the authority's budget.
The council employs 670 full-time staff and 567 casual workers.
In a statement, the council said a retrospective application will be made to furlough 152 staff and 170 casual workers and, going forward, an application will be made to furlough 205 staff and 170 casual workers. The number of employees being furloughed will be reviewed every three weeks and furloughed staff will be paid 100% of their salary until May 19, after which 80% of their wages will be covered by the government's job retention scheme.