The Georgian rebel region of South Ossetia invalidated Tuesday the results of a leadership poll which handed a surprise victory to a female opposition candidate in a blow to the Kremlin.

The supreme court decision plunged the tiny Russian-backed province into crisis, with parliament saying after an emergency meeting that South Ossetia would not hold new elections for its leader until March 25 next year.

The supreme court cited violations at the polls that gave ex-education minister Alla Dzhioyeva victory in a second-round run-off against Anatoly Bibilov despite his strong support from Moscow, the region's patron since Russia drove out Georgian forces in a 2008 war.

"The supreme court of South Ossetia has declared the presidential elections to be invalid," it said in a statement, claiming that illegal actions by Dzhioyeva's supporters posed a "threat" to voters.

Dzhioyeva will also be barred from running in the new elections, said outgoing strongman Eduard Kokoity.

"In accordance with the decision of the supreme court, considering the violations during the presidential elections in South Ossetia, Alla Dzhioyeva cannot participate," Kokoity said in comments reported by the Interfax news agency.

Dzhioyeva's supporters called the annulment of the bitterly contested vote a "power grab," while she herself condemned the court's actions.

"They contradict the conclusions of the observers who stated that the polls were conducted without violations," she said on the popular Russian radio Echo of Moscow, accusing court officials of exceeding their powers.

Dzhioyeva's victory came as a shock in a region where women in power are still a rarity.

Former wrestler turned politician Kokoity said this month that a female leader would be an unimaginable prospect.

"We have good relations with women in our society. But the Caucasus are the Caucasus," he told Russian mass-circulation newspaper Komsomolskaya Pravda.

Earlier in the day hundreds of Dzhioyeva's supporters took to the streets in protest against delays to the poll results in a rare public show of dissent in the heavily militarised region.

Some chanted "Victory! Victory!" as they rallied briefly in the central square of the dilapidated main town Tskhinvali before marching through the snow-covered streets.

Whoever ultimately wins the leadership will not however enjoy wide recognition as the "president" of South Ossetia, since the region is recognised as independent only by Russia and a handful of far-flung states.

Georgia said fair elections were impossible in a territory "occupied" by thousands of Russian troops stationed there since the 2008 war, when most ethnic Georgian inhabitants were expelled.

Georgian Reintegration Minister Eka Tkeshelashvili dismissed the showdown between Dzhioyeva and Bibilov as simply "infighting between two mafia clans" for control over Russian aid money.

"It has no political meaning -- one Russian stooge is being replaced by another. Regardless of who wins these pseudo-elections, no regime established through ethnic cleansing will be legitimate," Tkeshelashvili told AFP.

The West, which insists South Ossetia is an integral part of Georgia, has also condemned the elections as illegitimate.

The population of the tiny region is the subject of further dispute, with the rebel authorities claiming 70,000 while Georgia says the figure is no more than 15,000.