This will be the latest protest in a rolling programme of planned one-day strikes which started in June.
Over 100 social workers, who are represented by Unison, are protesting about the council's decision to award£3,000 pay rises to managers and£1,000 to a handful of front-line staff who work with the most vulnerable children. The majority of social workers will receive nothing.
The department, which is under special measures, has been struggling to maintain staffing levels since 22% of social workers left last year. The council claims it cannot afford to increase pay awards.
Unison says its members are further incensed by the council's decision to advertise for a children's central assessment team, offering new staff extra payments of£2,000.
After unsatisfactory negotiations with the council, social workers will continue the strikes. Sustained work-to-rule action from 28 August is also on the cards. This is likely to include refusing to co-operate with members, banning all out-of-borough visits to children's placements and residential care homes and overtime.
Irene Stacey, local branch secretary and National Executive Committee member of Unison, said: 'We'll be drawing up a hard-hitting programme of further industrial action and it will start before the end of the month.'
Edward Roberts, assistant director of social services, said: 'We are continuing our negotiations with the unions in the hope of achieving a satisfactory solution for our staff and services users.'