Newham LBC is facing a threat of strike action as it discusses proposals with about 5,100 workers, including senior managers, about reducing terms and conditions for some staff members.
Proposals include reductions to overtime, night, weekend, sick, and maternity pay.
Newham does not propose to make any changes to workers’ basic pay while any changes will not affect school-based staff.
A spokesman for the council said “less than a third of the centrally employed workforce could be negatively impacted” by the proposals.
Unite has threatened industrial action against the cuts which it says will save the council £1.8m.
The union’s regional officer Michelle Cook said the proposals were “not acceptable”. She said: “This is not a campaign demanding a pay increase – all we are demanding is that the pay and conditions of public service workers are not cut.”
Unite pointed to Newham’s general reserve fund which was worth £161m in 2015-16.
A spokesman for Newham said the council faced £42.6m cuts by 2020.
“With huge financial cuts to come, it is frankly ridiculous for Unite to blandly suggest that councils such as Newham use up their reserves rather than working with their staff to help balance the books in these tough times,” he said.
The spokesman said GMB and Unison, which represent 43% of the council’s staff, supported the proposals whereas Unite, which represents 13% of its workforce, had not. He added Unite “did not respond” to its formal consultation on the proposals.
Newham’s spokesman said the council was “committed to protecting frontline services and jobs” and added: “We are still considering the feedback we received from employees on the proposals. No formal decision has been made at this time.”