Russian authorities have refused to allow a new political party to field candidates in upcoming parliamentary and presidential elections, showing an unwillingness to allow the opposition any voice in the process.

The party was formed in December, and its application for registration — official status — was regarded as a test of government tolerance for a degree of electoral freedom. But the Justice Ministry announced Wednesday that it had rejected the application, saying the 46,000 signatures submitted as those of party members included names of the underage, the unregistered and the dead, leaving the party short of the 45,000 signatures required.

It also said it had received handwritten statements from “citizens” denying they had joined the party.

The People’s Freedom Party, known as PARNAS, includes leading lights of the opposition: Mikhail Kasyanov, a former prime minister; Boris Nemtsov, a former deputy prime minister; Vladimir Ryzhkov, a former member of the state Duma; and Vladimir Milov, a former deputy minister of energy. They denied that they had submitted invalid signatures.

The Kremlin has taken steps to create a malleable opposition party, but PARNAS represented a potentially uncontrollable threat from the outside. Prime Minister Vladimir Putin’s grip on the country is so firm that there was little chance that PARNAS would have come out an electoral winner, but government critics say those in power are fearful of offering opponents any foothold.

“It’s an irrational fear and another step in the direction of instability,” said Georgy Satarov, who was an adviser to Russia’s first president, Boris Yeltsin, and now heads the INDEM Foundation.

By trying to suffocate the opposition, he said, the authorities are closing off a means for Russians to express their mounting anger toward the system — it’s as though they are tying down a safety valve.

Kasyanov, co-chairman of PARNAS, said the decision could have been made only by Putin.

“It is clear that Putin has decided not to admit our party to the elections,” he told the Interfax news agency. “PARNAS’s participation in the elections would have involved serious risks for Putin’s vertical power structure.”

In years past, the democratic opposition has had little success in denting the popularity of Putin’s United Russia party. But there are signs that United Russia’s appeal has been waning, and Putin recently called for the creation of a Popular Front that might pull in voters disenchanted with the ruling party.

The PARNAS organizers thought they would have an opportunity to demonstrate United Russia’s weakness — if not actually to score significant gains in representation — when voters go to the polls later this year to pick a new parliament. Now it appears they have lost that chance.

“The upcoming elections cannot be considered free.”

Ryzhkov told the Itar-Tass agency there is no point in appealing the decision. “It is impossible to try to work with this regime within the bounds of the law,” he said.