Union claims of “rosters from hell” on the new night time Tube service are “not true”, London Underground (LU) has said.
Members of three unions will stage two 24-hour strikes on 25 and 27 August in the dispute over the proposals.
LU Managing Director Nick Brown said the unions had demanded more money, but unions claim their members wanted to protect their work-life balance.
Talks are due to resume between LU and the unions later.
Members of the Rail, Maritime and Transport (RMT), the Transport Salaried Staffs Association (TSSA) and Unite unions will walk out for 24 hours from 18:30 BST on Tuesday 25 August and at 18:30 on Thursday 27 August.
However, disruption is likely to be felt throughout most of that week owing to the timing of the strikes and the knock-on impact to the service.