Pro-choice supporters defied coronavirus restrictions forbidding gatherings of more than five people to take to streets lined with military police.
They marched to the house of the leader of the country’s ruling rightwing Law and Justice party (PiS) carrying black umbrellas, a symbol of abortion rights protests in Poland, and banners reading “I think, I feel, I decide” and “God is a woman”.
As in previous days, protests also took place in other Polish cities.
Small gatherings of far-right activists emerged from side streets in Warsaw firing flares on people taking part in the pro-choice demonstration.
Warsaw police tried to maintain a distance between the groups and much of the march proceeded peacefully.
Around a dozen people were detained, police said.
The protest, one of the largest demonstrations in Poland in years, follows a Constitutional Court ruling outlawing abortions in cases of severe foetal defects on 22 October.
The bill stripped away the most common of the few legal grounds left for abortion in Poland, with such pregnancies accounting for 96 per cent of terminations in the country.
After the ruling takes effect, women will only be able to access abortion legally in the case of rape, incest or a threat to their health.
Women seeking abortions have already been turned away from Polish hospitals even though the ruling is not yet enforceable, according to abortion rights support group Abortions Without Borders.
Central London earlier this evening. pic.twitter.com/ulg0bEkop6
— Kasia Madera (@BBCKasiaMadera) October 30, 2020
Earlier on Friday, president Andrzej Duda attempted to ease tensions by proposing legislation that reintroduced the possibility of abortions due to foetal abnormalities, although only limited to defects that are immediately life-threatening.
Mateusz Morawiecki, Poland’s prime minister, pledged lawmakers would proceed with the legislation quickly, but demonstrators were unimpressed.
“This is an attempt to soften the situation for PiS, but no sane person should fall for it,” Joanna Scheuring-Wielgus, an activist and leftist lawmaker, said.
Further protests were scheduled for Saturday, both in Poland and other European nations.