* Poll shows Conservatives would lose seats in election
* Shows they may not be able win stable minority
OTTAWA, July 14 (Reuters) - Canada’s governing Conservatives have a narrow lead in popular support over their main rivals but could struggle to form a stable minority government if an election were held now, according to a poll released on Wednesday.
The Environics survey said the Conservatives have the support of 35 percent of decided voters, one point down from a poll conducted by the same firm in May. The Liberals, the biggest opposition party, were up two points at 32 percent.
The poll is the latest in a string of surveys to show the Conservatives would most likely lose seats if an election were held now. The party retained power in October 2008 with 37.7 percent of the vote but still does not control a majority in the House of Commons.
Under Canada’s first-past-the-post electoral system, a party needs around 40 percent to gain a majority and 36 percent to secure a stable minority.
Environics said 31 percent of eligible voters did not know who they would vote for. Prime Minister Stephen Harper told Reuters last month that contrary to speculation, he was not looking for an election this fall.
Liberal leader Michael Ignatieff, who has had trouble engaging voters since taking up his job in December 2008, started a cross-country bus tour on Tuesday to boost his image. The bus broke down shortly after the trip began.
The Environics survey of 1,918 adults was conducted from July 5 to 8 and is considered accurate to within 2.2 percentage points, 19 times out of 20. (Reporting by David Ljunggren; editing by Peter Galloway)