MADRID – Berkeley Energia has appealed to Spain's Supreme Court against the nomination of new members to the country's nuclear safety council (CSN), which is due to assess the Australian company's uranium mine project near Salamanca.

The court, in a document released on Thursday, said it had rejected a request from Berkeley to urgently suspend a government decree last week which named four new members to the CSN's five-strong board, which rules on the safety of nuclear and radioactive facilities.

The proposed new members include an ecological activist, who has campaigned against Berkeley's mine project.

The court gave the government 10 days to offer its side of the story before deciding how to proceed.

The CSN needed to be reshuffled as most of the mandates were expiring. One of the tasks awaiting the new board is to assess Berkeley's only project in Spain, the as-yet unopened uranium mine, which sources told Reuters last year the Socialist government had decided to block.

The mine was granted preliminary approval in 2013 under a previous government, but still needs final authorisation. If the CSN approves the project, it is up to the government to give the green light, but if the CSN finds against it, the government cannot issue permits.

The court did not say what reasons Berkeley gave for its appeal. Berkeley and the CSN declined to comment.

The court also refused an urgent request from Spain's main opposition People's Party (PP) to suspend the nominations, which the PP said had been announced on the same day that the government called a snap election.

In a statement, the PP homed in on one of the new members, a doctor of physics named Francisco Castejon who has campaigned against nuclear energy generation, and specifically against Berkeley's mine, which would be located in Retortillo, near the northwestern town of Salamanca.

"The (PP) group has appealed to the Supreme Court because it was not able to debate the suitability of the candidates, particularly that of Francisco Castejon Magana," it said.

Castejon "is a known activist on anti-nuclear platforms and campaigns, which, in the opinion of the PP group, means that there is a clear conflict of interest", the group continued.

Ahead of a demonstration last year, Castejon tweeted: "I am going so that they do not open the Retortillo mine. So that they close the nuclear plants and we move towards a new energy model."

Spain's Energy Ministry and Castejon declined to comment.

Once the court receives the government's response to the appeal, it must decide whether to suspend the nominations. In the ensuing months, it will rule on whether they were legal.