The industrial action will affect the normal operation of schools, health and cultural venues among other sectors, Union leader Ana Aviola said.
The 24-hour strike will involve all services directly linked to the state services.
This is only the second strike since Prime Minister António Costa took office with the aid of a leftist alliance and the first of 2017.
The strike was called to demand wage increases, the payment of overtime and 35-hour working weeks for all civil services.
Labour and Welfare Minister Vieira da Silva has meanwhile played down the potential negative effect the strike will have on the growing confidence in the Government and its policies.