The 58-year-old lawyer -- who next week will mark the one-year anniversary of ex-president Nestor Kirchner's fatal heart attack -- has made gains with a more consensual style than her husband, against a fractured opposition.

"It's very emotional," Kirchner told journalists after voting in Rio Gallegos, Patagonia, 1,600 miles (2,600 kilometers) south of Buenos Aires, a day after visiting the tomb of her husband and political partner.

She could win with just 40 percent if her nearest rival is more than 10 points behind, but latest polls suggest she would sweep over 50 percent.

The center-left politician also hopes to win back control of the Congress, where 130 lower house seats and 24 senate seats are at play.

Argentina, a vast South American nation of 40 million, saw a booming economic growth -- aided by high world prices for its farm exports -- after Nestor Kirchner took office in 2003.

The late president, who had been expected to run for reelection, was credited with lifting the country out of its Greek-style financial meltdown of 2001 by restructuring massive debts and promoting spending.

Cristina Kirchner has vowed to push forward with popular social programs -- such as pensions and child benefits, as well as subsidies for transport and utilities -- and dismissed unofficial figures of rampant inflation.

Still dressing in black mourning garb, she has worked to improve relations with key sectors like industry and agriculture, after losing support in a dispute over taxes on farmers three years ago.

Kirchnerism belongs to the diverse and powerful Peronist movement of three-time former president Juan Peron and his populist second wife Evita.

Many Argentines see Kirchner's policies, which have been accompanied by a drop in both poverty and unemployment, as the safest bet for the economy amid uncertainty in Europe and the United States.

"I think it's the best we've got. Human beings have a right for basic help from the government, like pensions," said 63-year-old teacher Monica Bietti, after she voted in a Buenos Aires school.

"I don't think the other candidates would dare to stand up to the world over debts or anything else."

Kirchner's divided opponents have failed to convince they can do more to reduce runaway inflation -- which independent analysts estimate at more than 20 percent per year, more than double government figures.

Socialist candidate Hermes Binner has warned that Argentina, which relies heavily on exports to Brazil and China, will soon feel the effects of the global crisis, as growth is expected to slow down next year.

Binner, 68, is predicted to come second, more than 30 points behind Kirchner, while other rivals include 59-year-old Ricardo Alfonsin, from the traditional Radical Civic Union party and son of a former president.

In the most predictable elections since the end of the 1976-1983 dictatorship, many candidates have focused on winning seats in Congress.

Compulsory balloting for almost 29 million people began throughout the country at 8:00 am and was to close at 6:00 pm (2100 GMT).