Some 800,000 teachers, medical workers and other public sector employees are on strike to protest a law they say cuts their salaries.
Some schools were closed Monday and in others teachers were only supervising. Medical staff members are only treating emergency cases.
Police wore white armbands to show solidarity.
The Alliance of State Workers, a group of trade unions, is calling on the government to renegotiate a wage law, end lay-offs and stop unpaid vacation.
The government introduced new measures to cut budget spending in September by agreement with the International Monetary Fund, which has lent Romania US$17.1 billion.
Trade unions say they will stage a rally Wednesday in Bucharest to continue their protest.