BRATISLAVA (Reuters) - Slovakia stood on the verge of constitutional crisis on Monday as President Michal Kováč prepared to step down with no prospect of a swift replacement. No successor has been found for Kováč, who steps down later on Monday, because no political grouping in parliament, which elects the president directly, is strong enough to muster the three-fifths majority necessary to produce a winner. Important powers, such as the right to sign laws and appoint ministers, will be left in limbo but others such as the power to represent Slovakia abroad will pass to the government. A first round of voting was held in early February but the government did not nominate a candidate and none of those proposed came close to the three-fifths threshold. The next round takes place this Thursday but the government has again failed to nominate a candidate making deadlock all but inevitable. An indefinite number of new rounds could now ensue. Despite the constitutional problems which will arise as soon as the government wishes to pass a law or re-shuffle the cabinet, Prime Minister Vladimír Mečiar's spokesman, Jozef Krošlák said the situation was manageable and talk of a crisis was a gross exaggeration. "It's absolute nonsense. It's just opposition propaganda. If the opposition wanted to prevent what it calls a crisis, they could negotiate on the president," Krošlák said. Last year, opposition parties, with Kováč's blessing, helped to organise a referendum on a switch to a popular ballot in order to avert the parliamentary stalemate which was seen as inevitable even then. The government thwarted the referendum by removing a crucial question, but the constitutional court ruled this unlawful, and last week Kováč ordered the vote to be re-run in mid-April.