Polish President Bronislaw Komorowski on Thursday officially set the date of the country's parliamentary elections for October 9, according to dpa. The announcement launched a campaign that was likely to be dominated by controversy over what caused last year's plane crash in Smolensk, which killed then-president Lech Kaczynski and 95 others. Opinion surveys show the ruling centre-right Civic Platform party in the lead, with support of 39 per cent. The opposition Law and Justice party had 29-per-cent approval ratings, according to a poll released Wednesday by broadcaster TVN. Voters are to elect all members of both houses of parliament - 460 deputies in the lower house and 100 senators in the upper house - for four-year terms in office. Politicians had debated whether to hold voting over two days to raise voter turnout, but the Constitutional Tribunal ruled recently that two-day elections were unconstitutional. The Civic Platform has said the elections would not distract the government from its six-month rotating presidency of the European Union, which Poland assumed on July 1.