Abortion has been decriminalised in NSW after a bill, which had been the source of significant public and political debate in the past eight weeks, passed the Lower House on Thursday morning.

On Wednesday night, the controversial bill passed the upper house 26 votes to 14, paving the way for it to be reintroduced to the Lower House on Thursday.

MPs who had voiced opposition said they were more comfortable with its amended condition and even voted in favour.

Premier Gladys Berejiklian, who faced significant public criticism from conservative figures over the bill, was not in the chamber for the final vote.

Deep divisions in the Liberal Party have been revealed since Independent MP Alex Greenwich announced the introduction of the bill in July.

Liberal MP Tanya Davies, the strongest opponent of the bill, even plotted a leadership spill against Ms Berejiklian last week, but later backed down.

She had previously declared there was a “crisis of government” over the bill.

Throughout the past few months of debate far-right and religious groups attacked the government for trying to “rush” the bill through without enough public consultation.

But Ms Berejiklian intervened several times to allow more time for debate.

Federal Nationals MP Barnaby Joyce, and former prime minister Tony Abbott, both spoke out in opposition, with Mr Joyce describing it as the “slavery debate of our time”.

But NSW Nationals leader John Barilaro said he was proud to be part of a government that had decriminalised abortion.

“What we’ve achieved last night is historic for the state, decriminalising abortion, taking it out of criminal act and putting it in the health act where it should be, and not treating women like criminals,” he said.

The Catholic Archbishop of Sydney Anthony Fisher described it as a “dark day” for the state.

“The new abortion law is a defeat for humanity,” he said.

“[It] may be the worst law passed in New South Wales in modern times, because it represents such a dramatic abdication of responsibility to protect the most vulnerable members of our community.”

The Archbishop acknowledged the hundreds of protesters who maintained a vigil outside Parliament House, sometimes overnight, during the debate.

–ABC