Hackney Council faces a one-day strike by staff next week unless it withdraws new redundancy proposals.
Members of the GMB, T&G and Unison voted in favour of the one-day strike on Wednesday 20 December in protest at proposed job cuts and a reduction in redundancy payments.
Hackney Council is cutting staff in an attempt to reduce its significant budget deficit.
"We are looking for an immediate and unequivocal withdrawal of the council's proposals to cut redundancy payments," said GMB organiser Dawn Butler.
The council is locked in talks with staff and the unions in the hope of averting strike action.
"We are still working very hard towards reaching an agreement with unions so we can move forward," said Hackney councillor Eric Ollerenshaw, joint chair of the policy and finance executive committee.