Around 250 employees staged a sit-protest seeking pay rise on par with executives.
Unions for Bank officers have have unitedly opposed to the division in their ranks.
The German government has pressed for a fair bargain so that both parties are satisfied.
The demands will affect the lakhs of employees in the 1.55 lakh post offices in India.
Upset about not being given wage hike by the 3rd Pay Revision Committee, employees have declared a day-long nationwide strike on July 27