Political leaders are lamenting the "Americanisation" of the debate around a legislative push to increase access to abortion pills in Australia's most populous state.

The NSW parliament is examining an amended bill put up by Greens MP Amanda Cohn to address "abortion deserts" in the state and remove barriers to women terminating pregnancies in regional areas.

During a prolonged debate on Tuesday night, Opposition Leader Mark Speakman alleged in parliament that a prominent anti-abortion campaigner threatened to derail his leadership of the Liberal Party if he didn't oppose the bill.

Activist Joanna Howe told him she would have "no other choice but to suspend my planned campaign against Labor in order to lead a public campaign aimed at encouraging a grassroots opposition to you as Liberal leader", Mr Speakman told MPs in parliament under privilege.

"I will not cave to brazen bullying like this nor to the Americanisation of NSW politics," he said.

"I will vote according to my conscience and balance difficult and sensitive ethical, social, moral and medical concerns."

Premier Chris Minns backed his political rival, suggesting Dr Howe had spread "enormous amount of misinformation and lies" on her social media channels.

That includes a claim the bill would "force the closure of all Christian and Catholic hospitals unless they perform abortions" - a claim debunked by AAP FactCheck in March.

"It's whipped up a lot of good people in the community believing that the legislative changes are far more extensive than they in fact were," Mr Minns said.

Health Minister Ryan Park said misinformation and "bad faith characters" were both features of the debate.

"It's just classic misinformation, that people and nurses are going to be all of a sudden deregistered, and all of a sudden people will be made to go and do certain things," he told ABC Radio.

"Overly emotive (language) and misinformation can intimidate and scare people, particularly people who may have had a very personal experience (with abortion)."

The pared-back bill, expected to be passed on Wednesday, would allow nurse practitioners and endorsed midwives with appropriate training to prescribe medical abortion medicine, known as MS-2 Step, up to nine weeks of gestation.

Current laws in NSW only permit doctors to prescribe medications for abortions.

The proposed reforms would also require annual public reporting on service availability by region, wait times and any adverse events.

Both Labor and Liberal MPs have been granted a conscience vote on the legislation, which passed the NSW upper house in a reduced form.

The push for law change came after revelations a woman was turned away from having an abortion on the day of her planned procedure at Queanbeyan Hospital in August 2024.

Another public hospital in Orange restricted terminations for non-medical reasons, triggering the intervention of Mr Park to reinstate abortions without restrictions in October 2024.

Abortion was permitted by the courts in NSW in 1971 and decriminalised in 2019, but is not always accessible, particularly in rural and regional areas.

While the bill is likely to pass the NSW lower house, it will need to return to the upper house due to amendments.

That means the laws will not take effect until May 28 at the earliest.