Nov 23 (Reuters) - The Czech rightist Civic Democrats have widened their lead over the leftist Social Democrats as the country struggles through a parliamentary crisis that resulted from an inconclusive election, a poll showed on Thursday. Civic Democrat leader Mirek Topolanek was nominated as prime minister last week and is now searching to end the stalemate after leftist and centre-right parties each won 100 seats in a June general election. It is the second time since the June election that Topolanek has been appointed to the post. A minority Civic Democrat government lost a confidence vote in the lower house last month but remains in office as a caretaker administration. The Social Democrats, led by former Prime Minister Jiri Paroubek, were on 18.5 percent support, their lowest rating in any poll since the June election. The poll by the CVVM agency was conducted between Nov. 6-13 among 1,092 Czechs. DATE INSTITUTE ODS CSSD KSCM KDU-CSL Greens Nov 23 CVVM 29.5 18.5 8.0 5.0 8.0 Nov 15 STEM 31.5 20.7 10.9 7.5 9.4 Nov 10 FI 41.1 27.7 12.7 6.0 7.1 Oct 16 FI 35.9 27.2 13.9 6.9 8.4 Oct 15 STEM 32.0 22.7 11.7 6.3 10.5 Sept 22 CVVM 37.0 29.5 13.0 8.0 10.0 Sept 21 STEM 32.8 26.6 10.0 4.2 10.3 Sept 18 FI 36.3 32.0 13.7 6.5 7.3 Aug 7 FI 41 30.8 12.3 6.3 6.9 ---------------------------------------------------------------- June 2-3 election 35.4 32.3 12.8 7.2 6.3 NOTE. The parties are: - Civic Democratic Party (ODS) - right wing, liberal-conservative - The Czech Social Democratic Party (CSSD) - leftist - Christian Democratic Union-Czechoslovak People's Party (KDU-CSL) - centrist - The Communist Party of Bohemia and Moravia (KSCM) - far left - The Greens - environmentalists, centrist. Pollsters: The FI and CVVM results are based on a model predicting gains at the poll box, excluding those not willing to vote and undecided. STEM results are direct voter preferences, and include replies from all respondents including those not willing to vote. Parties should thus win a larger than indicated share of the vote at the election. (Reporting by Alan Crosby in Prague) ((Editing by ; prague.newsroom@reuters.com; Reuters Messaging: alan.crosby.reuters.com@reuters.net; +420-224 190 474)) Keywords: CZECH POLITICS POLL