SANTIAGO, Chile -- Chile's President Michelle Bachelet has issued a call for public debate on her proposal to ease one of the world's toughest abortion bans and was already getting some on Friday from the nation's largest opposition party.

Sen. Juan Antonio Coloma of Chile's conservative Independent Democratic Union said he was unfamiliar with the specifics of the bill Bachelet proposes to introduce to Congress later this year. But he said if it proposes the legalization of therapeutic abortion "we will not approve that idea."

The party's president Ernesto Silva noted that its members had rejected three past bills that aimed to legalize abortion.

Chilean conservatives in general are attacking Bachelet's plan to legalize abortion in cases when women have been raped, their health is in danger or the fetus won't survive.

Chile has banned abortions in all circumstances since the 1973-1990 dictatorship of Gen. Augusto Pinochet, and yet more than 100,000 illegal abortions are performed in the country every year.

"Chile has to face this reality by opening a mature and informed discussion and by taking up a debate in parliament on a measure to decriminalize voluntary abortion in rape cases, when the mother's life is in danger or when the fetus is not viable," Bachelet said in her state of the union address before Congress on Wednesday.

Chile has long been regarded as one of Latin America's most socially conservative countries. When it legalized divorce in 2004, it became one of the last nations in the world to grant married couples that right. When Bachelet, a physician, made the emergency contraception known as the "morning-after pill" available for free at state-run hospitals in 2006, it caused an uproar among members of the right-wing opposition, and even her allies.

Conservative lawmakers and former President Sebastian Pinera have strongly opposed the easing of the ban.

"It seems like there's more care and concern for the well-being of pets, than for the life and dignity of children who are about to be born," Pinera said via Twitter after Bachelet's speech.

But presidential spokesman Alvaro Elizalde said Thursday that abortion shouldn't be a taboo subject. "The Chile that we are building is for all of us, and we're going to encourage dialogue to solve the everyday problems of all Chileans," Elizalde said.

The Roman Catholic Church retains a strong influence over Chilean society, but attitudes toward abortion have been changing. Last year, the case of an 11-year old Chilean girl who became pregnant when she was raped by her mother's partner set off a national debate.