* Liberal had challenged victory by Conservative candidate
* Conservative won constituency by 26 votes
* Officials made errors; no fraud alleged before the court
* Conservative government retains substantial majority
* Liberal says people don't have confidence in system
OTTAWA, Oct 25 (Reuters) - The Supreme Court of Canada on Thursday upheld the election of a Conservative member of Parliament whose narrow victory was challenged by his Liberal opponent on the grounds that election officials had mistakenly allowed some people to vote.
The court ruled that administrative errors by Elections Canada officials should not disenfranchise the 52,794 people who voted in a west-end Toronto electoral district in the 2011 general election. Conservative candidate Ted Opitz won the Etobicoke Centre constituency by 26 votes.
"It should be remembered that annulling an election would disenfranchise not only those persons whose votes were disqualified, but every elector who voted in the riding," the court said in its 4-3 decision.
Liberal challenger Boris Wrzesnewskyj had said there were enough irregularities that the result in the district should be overturned, although he made no allegation of fraud or corruption in court hearings. A n Ontario court agreed with him and handed him the victory, but the Supreme Court overturned that ruling on Thursday.
Wrzesnewskyj had pointed out that, for example, some voter registration certificates were missing. The Supreme Court ruled that there was no direct evidence that anybody who was not entitled to vote ended up voting.
"The practical realities of election administration are such that imperfections in the conduct of elections are inevitable," Marshall Rothstein and Michael Moldaver wrote for the majority.
Chief Justice Beverley McLachlin led a dissent that emphasized the importance of elections officials following all procedures carefully.
"They are fundamental safeguards for the integrity of the electoral system," she wrote.
Wrzesnewskyj told reporters he accepted the court's decision, but he added: "People don't have confidence in the integrity of the system."
Opitz welcomed the court's emphasis on voters. "Fifty-two thousand people in Etobicoke Centre followed the rules, cast their ballots and today had their democratic decision upheld," he said in a statement.
The Conservatives were reelected in May 2011 with a majority of seats in the House of Commons. Including Opitz's seat, they have 163 of the 308 seats in the House. The Liberals have 35.
The results in seven other voting districts are being challenged separately in a lower court on the grounds that the Conservatives made misleading phone calls to voters, similar charges to those surrounding the U.S. presidential vote.