BERLIN Feb 28 (Reuters) - Five states controlled by the opposition Social Democrats (SPD) will challenge in Germany's highest court on Monday the centre-right government's decision to extend the lifespan of nuclear power plants.
Contesting the decision to keep Germany's 17 nuclear plants running for about 12 years beyond their original shutdown date, the states will file a challenge to the Constitutional Court, citing improper legislative procedure.
Simultaneously, the SPD and Greens Party will launch a separate challenge in the Court, also saying that the government's action was unconstitutional.
They are contesting the extension on the grounds that it was not put to a vote in the upper house of parliament, the Bundesrat, where Chancellor Angela Merkel's coalition lost its majority last year.
The states say the law should have come before the Bundesrat, where states are represented, because it gives them new responsibilities and saddles them with potential new costs.
The extension plan weighed on the popularity of the coalition when it was announced and stirred large-scale protests, which could resurface and hurt Merkel's Christian Democrats in six upcoming regional elections.
Several thousand opponents of nuclear power protested against the government's atomic policy on Saturday, forming human chains in some 40 cities and announcing further action on Monday.