UNITED NATIONS (Reuters) - Former Chilean President Michelle Bachelet announced on Friday she would step down from a key U.N. post amid high expectations that the popular politician would campaign again for the top job in her homeland at a November election.

Speaking at the end of a U.N. policy-making conference on women's rights, Bachelet simply said she would leave her role as executive director of gender equality body U.N. Women to go "back to my country."

The pediatrician-turned-politician's 2006 to 2010 rule was one of Chile's most popular presidencies, thanks to Bachelet's amiable style, welfare policies and steady economic growth in one of the region's most developed countries.

Chile's fractured left-wing coalition, which President Sebastian Pinera ousted from a 20-year rule, is hoping Bachelet will stage a comeback. Pinera belongs to the right-wing Renovacion Nacional party.

Bachelet, a victim of torture under the brutal dictatorship of Augusto Pinochet and a single mother of three, was one of conservative Chile's most unusual presidents since the return to democracy in 1990.

But her legacy was tainted by her government's slow response providing aid and halting looting after a devastating 8.8 magnitude earthquake in February 2010.

Under Chilean law, Pinera is banned from running for a second consecutive term. Former Public Works Minister Laurence Golborne, a charismatic businessman, and former Defense Minister Andres Allamand, a seasoned politician, are jostling to be the right-wing bloc's candidate.

About 49 percent of Chileans say they want Bachelet to be the country's next president, versus 11 percent for Golborne and 5 percent for Allamand, pollster CEP said in January.

Bachelet has led U.N. Women, a body for gender equality and the empowerment of women, since it was created in 2010 by the U.N. General Assembly.

U.N. Secretary-General Ban Ki-Moon on Friday praised her "visionary leadership" for giving it the start it needed.

"Her record of achievement includes new steps to protect women and girls from violence, new advances on health and a new understanding that women's empowerment must be at the core of all we do at the United Nations," he said in a statement.

"Her drive and compassion enabled her to mobilize and make a difference for millions of people across the world," he said.

(Reporting by Michelle Nichols at the United Nations and Alexandra Ulmer in Santiago; Editing by Todd Eastham)