Soldiers from the Nigerien presidential guard detained President Mohamed Bazoum on July 26 and went on to set up what they called a transitional government, one of a series of recent coups in West Africa's Sahel region.
That transitional government had told the Abuja-based ECOWAS Community Court of Justice that the sanctions, which included border closures by Niger's neighbors and a cut in power supplies by Nigeria, had led to a shortage of medicines and food, causing hardships.
The court dismissed the case saying the junta was not qualified to launch a case on Niger's behalf.
"The military junta is not a recognized government and is not a member of the ECOWAS state and therefore lacks the locus to institute this action. The case is hereby dismissed," Justice Dupe Atoki ruled.
Niger's junta led government in October said it had cut its planned spending for 2023 by 40% because of sanctions imposed after the July military power grab, further hobbling the economy in one of the world's poorest countries.
Niger had been a key partner for Western countries, including the United States, in the fight against Islamist insurgents who have killed thousands of people and displaced millions more.
However, the junta has since revoked security pacts with the European Union and former colonial power France. The West African nation also terminated two treaties with its former colonial power for cooperation and administrative assistance in tax matters.
ECOWAS leaders are set to meet in Abuja on Sunday for an annual summit which is expected to review the situation in Niger.
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