One of Austria's most prominent leftist politicians, Peter Pilz, gave up his parliamentary seat on Saturday after a woman alleged that he had groped her, in a scandal that further weakens the country's left-wing opposition.

The Vienna weekly newspaper Der Falter reported that the incident took place at a political conference in 2013, when Pilz allegedly was drunk and harassed a young staffer of the conservative European People's Party.

Pilz told a press conference that he does not recall the incident but takes the woman's account extremely seriously.

"I am very sorry to this woman, without knowing the exact details," he said, acknowledging that he "might really have done something wrong to a woman."

In addition, other media reported Friday that Pilz' former parliamentary assistant also claims that he sexually harassed her, but he rejected all of her charges as false. Her allegations were not the reason why he stepped down, he stressed.

Pilz had been a parliamentarian for the opposition Greens for more than three decades and was well known for uncovering corruption scandals, but he formed his own leftist party earlier this year after internal squabbles with the Greens.

In last month's election, Austria's conservative and far-right parties gained voter shares and are likely to form the next government.

While the Social Democrats stagnated and the leftist Greens lost all of their 24 parliamentary seats, Pilz' platform - called Liste Pilz - won eight seats in its first-ever election.

The scandal comes amid a global wave of charges of sexual misconduct against prominent men that started with allegations against US film producer Harvey Weinstein.