Former prime minister Tony Abbott has called for middle class women to have more children, saying current rates of childbirth among this group were a "real problem".

Mr Abbott, who tried unsuccessfully to get a generous paid parental leave scheme through Parliament, said conservative governments should try to encourage more working women to have more children.

Former PM Tony Abbott said low birth rates among middle class women is "a real problem in every western country." Credit:AAP

"While I'm all in favour of stay-at-home-mums if that's their choice, I do think that a properly conservative government, acknowledging that having a family is one of the most wonderful things that anyone can do, would make it easier for women in the workforce to have more kids," Mr Abbott said at the Centre for Independent Studies.

"That is a real problem in every western country: middle class women do not have enough kids. Women in the welfare system have lots of kids," Mr Abbott said. "If you're very wealthy you can afford to have as many kids as you want."