It will be debated in Parliament tomorrow, Tuesday, August 6.

The bill, if passed, will remove the "archaic" criminal penalties for abortion currently in place in NSW.

Mrs Williams joined with 14 other co-sponsors of the Reproductive Health Care Reform Bill from across the NSW Parliament.

This is the first Bill to be co-sponsored in the Legislative Assembly, with more co-sponsors than any other Bill in the Parliament's history.

The Bill introduced by the Member for Sydney Alex Greenwich on August 1 aims to bring NSW into line with other states and territories by regulating the termination of pregnancies as a medical procedure and decriminalising abortions.

It allows for terminations up to 22 weeks and later if two doctors "consider that, in all the circumstances, the termination should be performed".

It's believed to have wide cross-party support but there are some vocal opponents, including church groups.

Mr Greenwich said the bill was 119 years overdue, with women and doctors operating under an "out of date law".

The law criminalising abortion hasn't changed since 1900 - a time when women couldn't vote and there were no women in NSW parliament.

"Now, not only can women vote and stand for office, our state has a female premier, a female leader of the opposition and a female governor," he said.

"Women have fought long and hard for this reform, over many, many decades."

Mr Greenwich said the bill recognises the best outcomes in women's reproductive health care are achieved when abortion is treated as a health matter rather than a criminal one.

The draft law was designed in consultation with the Australian Medical Association, which says it will ensure access to appropriate care for women.

Mrs Williams said she will be supporting the Bill that offers protection for women, doctors and healthcare workers from prosecution for conducting and or assisting in a termination.

"Currently in NSW, it is a criminal offence to procure an unlawful abortion. This law has not changed since the Crimes Act was written in 1900," Mrs Williams said.

"Members from all political persuasions and communities across NSW have come together to ensure women in NSW can get access to safe and legal abortions and that the doctors have the legal certainty they have long asked for.

"This Bill, if passed, will bring NSW in line with every other State and Territory where abortions have been decriminalised and women and doctors are no longer stigmatised because of our archaic laws.

"The Reproductive Health Care Reform Bill 2019 will regulate the practice of terminating pregnancies in NSW, bringing the law into line with clinical practice, community attitudes and the rest of the country," Mrs Williams said.

Premier Gladys Berejiklian backs the bill and said there has been a "strength of feeling" across the political landscape on the issue.

It's supported by the NSW Nurses and Midwives' Association which labelled the state's current law unjust and against women's reproductive rights.

Australian Lawyers for Human Rights said the bill, if passed, will remove the "archaic" criminal penalties for abortion currently in place in NSW.

Before the bill was presented, about 200 people picketed outside NSW Parliament at an anti-abortion Rally for Life.

Many held signs saying "pregnant women need support not abortion" and "we love life on both sides of the womb".

The bill also came under fire from former deputy prime minister Barnaby Joyce who used his baby son to criticise the NSW proposal.

"Long before he was born ... Tom had rights even though he was not conscious of them - they should not be removed by a parliament," he told the lower house in Canberra. The hour of birth is an arbitrary point in modern medicine."

Supporters of the bill led by Pro-Choice NSW are expected to rally ahead of debate in the parliament tomorrow (Tuesday).

Speakers will include Rev Dr Margaret Mayman of the Uniting Church; cross-party NSW politicians Penny Sharpe, Jenny Leong, Alex Greenwich; Wendy McCarthy Chair of the NSW Pro-Choice Alliance; and Natalie Lange, Secretary of the ASU NSW Branch representing workers in health centres, community legal centres and refuges.