A court in Agadez, in a ruling handed down on Monday, issued the suspension against the mining firm SOMIDA, majority owned by Canada's Global Atomic, which symbolically broke ground at the nearby site last November.
A collective of civil organisations asked the court in January for renewed environmental impact studies it alleged were "slapdash" and carried out without sufficiently consulting the residents.
Niger is one of the world's biggest sources of uranium, which nations worldwide are looking to as a source for nuclear power that could reduce reliance on fossil fuels.
But safety fears and environmental concerns over the disposal of toxic nuclear waste remain, meaning the impoverished and landlocked Sahel state has yet to see a boom in mining.
Global Atomic owns 80 percent of SOMIDA while the Niger state owns 20 percent.
"The judge accepted the grounds for all our claims," said Barka Alhassan, director of the collective that filed the suit.
The company has 15 days to appeal.