Between 300 and 400 employees on the morning shift halted work at two logistics centres in Bad Hersfeld in the west of Germany, said Mechthild Middeke, a representative of the giant service-sector union Verdi at Amazon.
The union is calling for three days of strikes at both Bad Hersfeld and Leipzig, with a demonstration planned in Leipzig on Friday.
Verdi has been trying for months to get Amazon to bring the pay of its 9,000 workers in Germany in line with wages in the distribution sector.
Amazon refuses, arguing that its distribution centres are logistic sites and that it pays its staff accordingly. Wages in the logistics sector in Germany are lower than in the distribution sector.
Employees staged a number of walkouts already in May and June. "Amazon can expect further strikes," said Joerg Lauenroth-Mago, who is in charge of pay negotiations in Leipzig. "With the Christmas season coming up, that's going to hurt."
Amazon's German headquarters are in Munich. But it also operates eight logistics centres and two customer service centres.
Some 3,300 people work on two sites in Bad Hersfeld and 2,000 in Leipzig in the east of Germany.
Amazon's employment practices were the subject of a critical documentary broadcast on German public television at the beginning of the year.