The Verdi union wants to expand its strike at the Vivantes clinic and at the Charité this Tuesday.
It is planned to increase the number of locked beds to 1200, said union secretary Kristof Becker of the German press agency.
In the afternoon (4 p.m.), according to Verdi, a demonstration march is also planned from the Charité hospital ward to the Red City Hall.
On Monday, 900 hospital beds were blocked, including 600 at Vivantes and 300 at the Charité.
More than 1000 employees want to go out of work every day to put pressure on for relief and fair pay, announced Verdi negotiator Meike Jäger.
Vivantes and Charité are state-owned companies.
There are a total of around 8,300 beds in the clinics.
The union had rejected a new tariff offer from Vivantes on Friday.
On Thursday, employees in the Vivantes and Charité clinics went on an indefinite strike.
You advocate a collective agreement for relief at both institutions.
The Vivantes subsidiaries are also about better working conditions and money.
Verdi guarantees that emergencies and patients who are in hospital for inpatient treatment will be taken care of.