Berlin - The Christian Democrats (CDU) in the German port of Hamburg approved Monday a groundbreaking coalition with the Greens, putting the final seal on the first-ever coalition between the two parties at state level.

CDU members voted unanimously to approve the 65-page deal hammered out between the executives of the two parties earlier this month, following February 24 elections that left the CDU without an absolute majority in the state legislature.

The way was cleared for CDU Mayor Ole von Beust to be confirmed in office on May 7, when the legislature meets, after the Greens had approved the unique agreement on Sunday.

The CDU and the Greens, known in the city state as the Greens- Alternative List (GAL), together have 68 seats in the 121-seat legislature.

The new senate, as the Hamburg cabinet is called, is to have six CDU and three GAL senators.

Although there are several deals with the CDU at local level, the Greens have never before entered into government alongside the CDU at state or federal level, preferring to strike deals with Germany's other major party, the Social Democrats (SPD).

In the deal, the GAL has agreed - against previous decisions - to allow the River Elbe to be dredged to a greater depth so that the largest container ships can enter the port, Europe's third largest after Rotterdam and Antwerp.

Another serious point of difference is a coal-fired power station at Moorburg within the city limits. Construction has started, although final approval for the power station - a modern plant that also heats buildings - still has to be granted. (dpa)