Family First Senator Steve Fielding has been condemned by other senators for suggesting women might have an abortion after 20 weeks to try to claim paid parental leave.

The paid parental leave legislation, which is being debated in the Senate, allows for women who have stillbirths to claim the payment.

During debate, Senator Fielding raised concerns that some "drug addicts" or "welfare cheats" could deliberately fall pregnant, then have an abortion after 20 weeks and rort the system in order to be eligible for payments.

"Drug addicts and welfare cheats can go out there and get themselves pregnant and then after 20 weeks have an abortion and still pocket the Government's cash," he said.

However, the Government says women who choose to have an abortion are not eligible for paid parental leave.

But Labor Senator Ursula Stevens says the laws are clear.

She says a medical practitioner must certify that a stillborn child was delivered before the Government payment is made.

"The notion that someone would for the purposes of receiving the baby bonus or paid parental leave would proceed to a post 20-week pregnancy and then procure an abortion for that purposes is really the most incongruous thing that anyone might consider could happen," she said.

Nationals Senate Leader Barnaby Joyce was angered by Senator Fielding's comments, accusing him of a "base form of politics" by bringing abortion into the debate.

"It is contemptuous to believe that you are working what I would suggest is a wedge, what I would suggest is a political chess manoeuvring by the most minor pawn in the most base way for a certain outcome what I don't believe its genuinely held," he said.

The scheme is due to start on January 1 next year. It will provide for 18 weeks of paid leave at $543 a week.