The planned cuts come after the partnership moved to slash redundancy payments in half in an effort to make job cuts more affordable. Staff responded to the update in internal forums to say they were planning to consult trade unions.
Dame Sharon late last month told employees to prepare for “quite big changes and quite bold changes”.
Staffing accounts for one of John Lewis’s biggest costs and in the last financial year, it spent £1.8bn in total on employees.
The growing threat of strike action follows criticism from union bosses last week over how the partnership has handled redundancy pay changes.
The GMB also accused John Lewis of discouraging workers from joining trade unions, something that was rejected by the partnership. It has its own partnership council, where staff elect representatives to vote on policy changes.
John Lewis said staff were “free to join a union”. A spokesman added that “as an employee-owned organisation, we… provide many benefits of a union, without any cost”.