The upper house began debating amendments to the bill on Tuesday afternoon following the threat of a leadership spill against Premier Gladys Berejiklian over her handling of the private member's bill.

In its current form, the Reproductive Health Care Reform Bill 2019 would allow terminations up to 22 weeks as well as later abortions if two doctors agree.

The chamber on Tuesday debated, among others, an amendment seeking to move the trigger for further medical oversight when a woman is having an abortion from 22 to 20 weeks.

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Greens MP David Shoebridge delivered a scathing criticism against the amendment.

"There's been a series of contributions from men, largely without medical training on why they think the threshold should change," he said, adding that his position was guided by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

"What possible basis can a bunch of men, with no medical expertise, be challenging that?"

The upper house heard a number of times that changing the threshold would unfairly disadvantage poorer women and those in regional areas.

However, proponents of the amendment argued NSW needed to improve it's health care if that was the case.

Labor's Penny Sharpe said she would be happy to "reach across the aisle" and work with parliament to increase funding and access to address that issue, but warned that this was distracting from the actual issue at hand.

"We're not dealing with what we want to happen, we're dealing with what's actually happening now and how do we make that safe, and how do we make that legal," she said.

Despite a last-ditch effort by Christian Democrat MP Fred Nile to argue for the amendment in the hopes of saving at least one more life, it was rejected by the upper house.

The debate continues.

AAP