A Florida judge has rejected a US Congress candidate's request to examine the source code of electronic voting machines alleged to have miscounted votes in November's mid-term elections.

Judge William Gary of Florida's Second Judicial Circuit rejected the request by Democratic candidate Christine Jennings, saying the source code for the ES&S (Election Systems & Software) e-voting machines used in the election is a trade secret.

Jennings, who lost by 369 votes in the 13th Congressional District race, has sued voting officials in Sarasota County, Florida, over discrepancies in the way votes were recorded. More than 18,000 people who cast votes in other district races failed to have votes recorded in the congressional race. For example, about 4,000 more votes were recorded for the county's Southern District Hospital Board than in the House race.

Jennings and district voters who brought the lawsuit want access to trade secrets "based on nothing more than speculation and conjecture", Gary wrote in his ruling on Friday. Allowing the plaintiffs access to the source code "would result in destroying or at least gutting the protections afforded those who own trade secrets", the judge wrote.

Jennings, on her website, wrote that she would appeal against Gary's ruling. "It's shocking that there is more concern for protecting a company's profits than protecting our right to vote," Jennings' site said. "The secrecy and question marks surrounding electronic voting is creating a real crisis in confidence among America's voters, and the only way to resolve this is by conducting a thorough review by outside experts."

Jennings' opponent, Republican Vern Buchanan, will be seated in the US House of Representatives while Jennings continues to seek a revote in the election.

An ES&S representative wasn't immediately available for comment on Monday.