Santiago (AFP) - Michelle Bachelet, Chile's first woman president, said Tuesday she will never again seek public office after her term expires in 2018, as a corruption scandal involving her son batters her popularity.

"It's obvious I will never be a candidate again for any elected political office," she told journalists.

Bachelet has been a towering figure on the Chilean political scene since first winning the presidency in 2005.

She left office in 2010 with an approval rating of 83 percent, then, barred from serving a second consecutive term, surged back to power in the December 2013 election, winning 62 percent of the vote and becoming the first president to serve more than one term since Chile's return to democracy in 1990.

But her popularity has tumbled to around 30 percent since accusations emerged that her eldest child, Sebastian Davalos, used his political influence to get his wife, Natalia Compagnon, a $10 million bank loan.

Compagnon's company used the money to buy property that was then slated for urban rezoning, selling the land at a $5 million profit.

Bachelet denies any prior knowledge of the loan, but the scandal has seriously dented her image as a reformer.

Under Chile's constitution, which bars consecutive presidential terms, Bachelet is not eligible for immediate reelection, but she could serve in Congress or other elected office.

Bachelet said Chile was suffering a "crisis of confidence" over the scandal and two others involving tax fraud and illegal campaign contributions by two of the country's largest companies, the Penta group and mining firm Soquimich.

"I'm worried by this climate of suspicion in the face of everything," she said.

Bachelet said earlier this month she has no plans to resign.