Former deputy prime minister Barnaby Joyce has weighed in on the NSW abortion debate, saying state MPs pushing for a bill to decriminalise abortion would have considered his infant son "subhuman".

Key points: The Federal Member for New England said the hour of birth was "an arbitrary point in modern medicine"

The Federal Member for New England said the hour of birth was "an arbitrary point in modern medicine" Mr Joyce is supporting six children across two families

Mr Joyce is supporting six children across two families The bill was introduced into the lower house of the NSW Parliament on Thursday

The Member for New England and his former media advisor, Vikki Campion, had their second child on June 1.

On Thursday in Federal Parliament, Mr Joyce invoked his son's name to attack NSW politicians sponsoring a bill to decriminalise abortion.

"In the NSW Parliament they are debating whether Tom had no classification of human rights," Mr Joyce said as Labor MPs heckled him from across the chamber.

"To say he didn't have the rights of other human life is to say he must be subhuman."

Mr Joyce said "the hour of birth is an arbitrary point in modern medicine", and that his son had an "indivisible right" to be alive.

"Tom had rights, even though he was not conscious of them. They should not be removed by a parliament," he said.

Mr Joyce has been a prominent figure in the abortion debate in Australia, having lobbied the NSW Nationals last June to vote against a bill that would create exclusion zones for protesters outside abortion clinics.

Last week, he tried to walk back comments he made to a newspaper in which he claimed his $211,000 income was "spread thin" because he was supporting six children across two families.

He has four children with his former wife, Natalie, and two with Ms Campion.

Protestors outside the NSW Parliament could be heard in the chamber. ( ABC News: Nour Haydar )

The bill, which Mr Joyce was lambasting, entered NSW Parliament.

It would remove abortion from the Crimes Act and treat it as a medical procedure and allow a termination at up to 22 weeks' gestation.

After this period, a woman would need the consent of two doctors.

Melanie Fernandez, a Pro-Choice NSW spokesperson, said she found Mr Joyce's comments in Parliament "very disappointing".

"Barnaby Joyce as a Federal Member is not going to be voting on this bill," she said.

"We know Mr Joyce has a history of intervening ... but this is a matter for NSW Parliament and for the women of NSW."

Independent MP Alex Greenwich apologised to the women of NSW as he introduced the bill to the lower house.

"I am sorry it has taken so long to achieve this reform," he said.

"Now is the time to come together to ensure women and their doctors are appropriately protected under the law."

In the Parliament. more than 20 cross-party MPs erupted in applause when the bill was introduced.

Mr Greenwich and Health Minister Brad Hazzard, who is a co-sponsor of the bill, shook hands.

Members of the Pro-Choice Alliance, who support the bill, were in the public gallery, while outside Parliament hundreds of people protested against it.

They could be heard in the chamber.

The introduction of the bill had been delayed after conservative Liberal MPs called on the Premier to give them more time to consider it.

It will now be debated and voted on next week.