BRATISLAVA (Reuters) - The Slovak Supreme Court rejected on Friday an attempt by Prime Minister Vladimír Mečiar`s ruling party to exclude the main opposition grouping from next month`s parliamentary election. Mečiar`s Movement for a Democratic Slovakia (HZDS) on Monday contested the right of the largest opposition grouping, Slovak Democratic Coalition (SDK), to register for the September 25-26 vote. Slovak media quoted HZDS representatives as saying that the SDK, which was formerly an alliance of five parties, could not technically register as a single party. But the court ruled that HZDS`s objection was groundless and accepted the registration of the SDK as a single party. "The court has prevented the destruction of the democratic system in Slovakia," SDK leader Mikulas Dzurinda said after the ruling. "The decision of the Supreme Court means victory for the right over HZDS ill will," he said. HZDS said it would not immediately comment on the court`s ruling. "We will release the party statement later," a HZDS press official told Reuters. Opinion polls suggest the combined opposition would win the election with a large majority over the ruling coalition dominated by HZDS. An opinion poll by the private MVK agency at the end of July showed 37 percent support for the governing coalition and 59.6 percent for opposition parties. The SDK itself had 23.2 percent support against 27.4 percent for HZDS. Slovakia has been excluded from the first wave of European Union and NATO accession talks because of concerns that it is backsliding on democratic reform.