A bill to decriminalise abortion has been voted down in New South Wales Parliament.

Members of the public gallery yelled "shame" as it was announced the bill had been defeated 25 to 14.

Greens MP Mehreen Faruqi's bill sought to have offences relating to abortion removed from the Crimes Act and common law.

It also required doctors who objected to abortion to refer patients on to a doctor who would help them and to install 150-metre safe access zones around abortion clinics to prevent the harassment of staff and patients.

Both pro-choice and pro-life protesters lined up in front of Parliament ahead of the debate and the public gallery was packed with supporters and opponents of the bill.

MPs from both sides of the chamber were granted a conscience vote on the issue — but a number of pro-choice MPs expressed concerns about details of the bill.

Dr Faruqi said that the fight to decriminalise abortion would continue despite the voting down of her bill.

Barriers greater for disadvantaged

Labor MP Penny Sharpe, who has also written a bill to install safe access zones around abortion clinics, spoke in support of Dr Faruqi's bill.

"These laws are now 116 years old, after 116 years these laws are no longer in line with community expectation or modern medical practice," she said.

"Abortion should be regulated in the same way as all other surgical and medical practices. Our current law is archaic and unclear."

Ms Sharpe expressed concern socially disadvantaged people had more obstacles to abortion access.

"[The law] creates barriers for patients and for doctors. These barriers are greater for those who are already disadvantaged."

Opposition concerns over bill's legal framework

Labor's health spokesperson Walt Secord voted for the bill as he is pro-choice — but expressed concern that it left no legal framework to allow medically approved abortions to occur.

"As the shadow health minister for the last three years I have not received a single representation on abortion or the need for legal clarification — until [Dr Faruqi] began her campaign," he said.

"Dr Faruqi's legislation has not provided a legal framework to allow medically approved abortions to occur. She's removed that — with nothing in its place.

"The bill in its current form places no limit on the gestation at which an abortion can be performed, it does not mandate if it can be performed by a clinician, it does not provide a framework, it just takes [it] away."

'Historic day for women's rights'

Dr Faruqi said that current medical and criminal laws would continue to protect patients.

"All these professions are regulated under the Health Practitioner Regulation National Law and they will continue to stop unqualified people form practising as doctors, pharmacists or nurses," she said.

"Anything done without the permission of the woman is now and would continue to be grievous bodily harm which carries substantial penalties.

"This bill does not change current medical practice on late-term pregnancy termination and to suggest otherwise is misinformed."

Despite the defeat, Dr Faruqi said it was an historic day for women's rights in New South Wales.

"This is only the start we have created overwhelming momentum and we will only move forward from here," she said.