Michelle Bachelet is expected to overwhelmingly win Sunday's presidential election and possibly avoid a runoff, riding a wave of hope that brought millions of Chileans to the streets demanding social change.

The 62-year-old former political prisoner has taken up the cause of protesters demanding education reform, greater environmental protection and a reduction of Chile's sharp income inequality.

Thursday is the last day of campaigning for elections that will also choose 120 members of the lower House of Congress and 20 out of 38 Senate seats.

But getting elected to a second four-year term as Chile's first and only female president is likely to be the easy part for Bachelet. Analysts say she'll have a harder time pushing her agenda through Congress.