BRATISLAVA (Reuters) - Public support for Slovak Prime Minister Vladimir Mečiar's populist coalition government has dropped since a political crisis erupted in early March, an opinion poll said. Support for the government, which has faced a barrage of criticism at home and abroad for the way it has handled the crisis, dropped to 33 percent from 36 percent in the last poll in January. Combined support for the opposition rose to 59 percent from 55 percent. The poll, conducted by the private Focus agency, is the first survey of public opinion since Slovakia was plunged into constitutional crisis on March 2 when President Michal Kováč, stepped down at the end of his term leaving no successor. Mečiar's government was sharply criticised by the European Union and the United States for the way it used its new powers. The most controversial moves came when Mečiar cancelled a referendum called by Kováč aimed at changing the method of selecting the president to a direct vote of the people from the current vote in parliament. The constitutional crisis itself arose because parliament is too divided to agree on a replacement for Kováč and the referendum was called to avoid repeated rounds of inconclusive voting. Mečiar also used presidential amnesty powers to prevent prosecutions over another referendum he cancelled last year and over the kidnapping of former president Kováč's son in 1995. Despite the opposition's strong showing in the poll, it is united only in its opposition to Mečiar. The opposition comprises the free-market Slovak Democratic Coalition with 29 percent, a reformed communist party, the Party of the Democratic Left, with 9.0 percent support, an ethnic Hungarian grouping, the Hungarian Coalition, with 10 percent support, and the Party of Civic Understanding which has yet to publish a political programme and has 11 percent. Despite greater unity among the three government parties, one, the Workers Party with 3.1 percent support, would fail to gain any representation at all in parliament because it has fallen below the five percent threshold necessary to gain any seats. This would reduce Mečiar's effective support to around 30 percent. Mečiar's own party, the Movement for a Democratic Slovakia (HZDS), has the support of 24 percent of voters and the Slovak National Party has just under seven percent. The poll was conducted among a representative sample of 1,088 respondents. Just over 26 percent either would not vote or are undecided, the poll said.