POLITICS IN ARGENTINA: President Cristina Fernandez won primary and still the front-runner for October elections

Polls open in Argentina's presidential

President Cristina Fernandez de Kirchner is seeking a second four-year term.]

Candidates pose for cameras as they cast their ballots

Cristina Fernandez de Kirchner, seen as the front-runner, is seeking a second term

The contest is Argentina's first presidential primary

The primary vote is seen as a key test of Fernandez's popularity

Buenos Aires.- Argentinians braved long lines and cold weather Sunday as they went to the polls for the country's first-ever presidential primary, a vote that could serve as a key litmus test of incumbent President Cristina Fernandez de Kirchner's popularity.

Bundled-up Argentinians cast their ballots in schools and community centers, choosing from ten presidential candidates.

Fernandez voted in her home city of Rio Gallegos, in the Patagonian province of Santa Cruz, where temperatures on Sunday were below zero. She is seeking a second four-year term.

Polls show that while Fernandez's popularity has waned, she remains the front-runner.

"This primary not only serves the government so it can define its position, but it also serves the opposition, so they can do some fine-tuning to their strategies and create possible alliances," pollster Graciela Romer told CNN en Español.

Sunday's primary vote is expected to reveal whether she will win outright on October 23 or be forced into a runoff election.

Fernandez needs 45%, or at least 40% and a 10-point lead, over her nearest rival to win in October.

"If the election were held today, opinion polls show that (Fernandez) would win with 42 or 43% of the votes, followed far behind by Ricardo Alfonsin with 17 or 18%, and then by ex-President Eduardo Duhalde," Romer said.

Alfonsin, the opposition candidate with the strongest poll numbers behind Fernandez, voted in the town of Chascomus, in the province of Buenos Aires, where some 40 percent of national voters reside. The son of late President Raul Alfonsin, he is a member of the Radical Civic Union Party and is seen as short on significant political experience.

Duhalde, also expected to be amongst the top challengers in October, voted in the city of Lomas de Zamora, in Buenos Aires province. He posed for cameras as he placed his sealed ballot in the box.

"I am happy to have been able to come and cast my vote in this important primary. I hope a lot of people vote today, because that is what we need in a democracy," Duhalde told reporters.

Fernandez, Argentina's first elected female president, was married to former President Nestor Kirchner, who died last October. If re-elected, Fernandez has said that her second term will be dedicated to her late husband's memory.

On Sunday, Fernandez posed for photographers and exchanged kisses with locals in Rio Gallegos. She wore a heavy coat and was, in her trademark style, immaculately coiffed.

"This is a fantastic day and we are participating in a historic process," Fernandez said.

"We are building the most important political reform in the country since democracy returned in 1983," she said.

Voting is obligatory in Argentina and some 28 million people were eligible to vote in Sunday's primary.

Candidates must receive at least 1.5 percent of the overall vote on Sunday to be on the ballot on October 23rd.

Voting stations will stay open until 6 p.m. (5 p.m. ET).