County Kerry, Ireland (CNN) Voters in Ireland cast their ballots in a landmark referendum to decide whether to remove a constitutional amendment that bans abortion in almost all circumstances.

Some 6,500 polling stations across 40 constituencies in the republic closed at 10 p.m. local time (5 p.m. ET). Counting of ballots will get underway on Saturday, with a result expected by mid-afternoon.

An electorate of around 3.2 million people were eligible to cast their ballots, including thousands of Irish people living overseas who have flown home to vote.

If the Yes campaign wins, Irish lawmakers are expected to enact legislation allowing for terminations in the first 12 weeks of pregnancy -- and later in cases where there is a risk to the mother's life or the fetus is not expected to survive.

A No vote would keep Ireland's abortion laws -- some of the strictest in the developed world -- in place.