President Cristina Fernandez on Thursday celebrated a new law that lowers the voting age to 16, a move that could have a big influence in next year's congressional elections.

The law that won final approval Wednesday evening expands "the rights of our young people so that they can use one of the most important weapons, the showing their opinions at the voting booths," Fernandez said.

The change adds 1.4 million young voters, expanding the electorate by close to 5 percent.

The government has tried hard to court these voters. The ruling party and its allies control congress, but they lack the two-thirds majority in both houses needed to change the country's constitution.

Opponents fear Fernandez could then eliminate term limits and rule indefinitely. Fernandez was reelected in October 2011 with more than 54 percent of the vote. If her opponents can manage to hold onto enough seats in the House and Senate next year, they can prevent any constitutional changes until after her second term is over in 2015.

Despite rampant speculation about a "re-re-election," Fernandez has kept both supporters and opponents in line by declining to define her plans.

Ruling party Deputy Diana Conti, who presides over the lower chamber's constitutional commission, ridiculed term limits as "stupid."

"If the main thing is to alternate leaders and alternating means putting in someone inept, democracy and even civil society suffers," she told Radio Continental on Wednesday.