Speaking at the main trade union rally of the day, Michael Sommer, chairman of the umbrella DGB labor federation, demanded a statutory minimum wage of 7.50 euros ($10) an hour.
People in Nuremberg demonstrated as a response to a right-wing march
Millions in Germany are on "starvation wages," DGB labor federation chairman Michael Sommer told trade unionists on May Day in the Ruhr town of Gelsenkirchen. He was at one of the many labor rallies held across the country on Tuesday.
Other trade unionists speaking at Labor Day rallies echoed his call.
Annelie Buntenbach, a board member of the DGB, Germany's labor union umbrella group, said in Berlin: "We will not accept hearing the champagne corks pop on the top floor, while an increasing number of people do not know how they will make ends meet."
Merkel's Christian Democrats (CDU) rejected the call.
"Minimum wages do not create jobs, but rather, destroy jobs," CDU General Secretary Ronald Pofalla said.
Jürgen Peters, chairman of the powerful IG-Metall engineering workers union, warned in Hamburg that the current token strikes in the sector could grow into a full-blown industrial action.
"If there is no peaceable solution at the negotiating table, we will take our share in the current boom by other means," the head of Germany's largest union warned.
Strikes since Sunday
Police arrested over 60 in Berlin during the night
IG-Metall has called rolling "warning strikes" lasting up to two hours at plants across Germany since early Sunday in support of a 6.5-percent pay rise for the sector's 3.4 million workers.
Employers in the key export sector have offered 2.5 percent plus a one-time bonus of 0.5 percent.
Peters also attacked plans to lay off around 8,000 workers at Airbus, almost 4,000 of them in Germany, accusing management of responsibility for the two-year delay to the production of the A380 superjumbo and the resulting losses.
In Nuremberg in the southern state of Bavaria, a march by some 200 members of the right-wing nationalist NPD party was met by a counterdemonstration of up to 5,000.
Bavarian Interior Minister Günther Beckstein called for democrats to "stand together whether against old or new Nazis," as stones and bottles were thrown.
Left vs. Right
Labor union chairman Michael Sommer
In the Thuringian city of Erfurt, a march of 1,300 right-wingers was blocked by a similar number of leftists. Police made 60 arrests after they were attacked and cars were damaged.
Dortmund saw similar protests. Rail lines were closed after demonstrators started fires on the tracks.
In Leipzig in the states Saxony, following a rock concert against right-wing extremism Monday night, 1,000 people assembled on a square and threw missiles, injuring 18 police officers. Police made 25 arrests.
Berlin police contained overnight street disturbances that have become a 20-year tradition in the German capital, detaining 61 rioters in the eastern part of the inner city.
The disturbances during "Walpurgis Night" were at Boxhagener Square in the Kreuzberg-Friedrichshain district.
According to German folklore, Walpurgis Night, the night from April 30 to May 1, is the night when witches hold celebrations to mark the arrival of spring.