The Fairfax MP has come under fire after accusing the government in Parliament on Monday of designing its paid parental leave scheme ''just so that the Prime Minister's chief-of-staff can receive a massive benefit when she gets pregnant''.

Leader of the House Christopher Pyne immediately demanded an apology from Mr Palmer but the Palmer United Party leader was unrepentant on Tuesday, issuing a further attack on Ms Credlin as having "undue" influence on the government.

Government MPs who have swooped on the comments have highlighted their insensitivity given Ms Credlin’s highly publicised struggle to have a child through IVF.

Foreign Minister Julie Bishop said on Tuesday the remarks were “particularly hurtful” and said Mr Palmer should think twice before making such personal attacks.

''I hope Mr Palmer reflects on what he says,'' she told Sky News.

''Of course he can debate policy but he shouldn't debate staff members in doing so.''

Mr Palmer on Tuesday stood by his comments and said that he was not aware of Ms Credlin’s personal struggles.

He also denied that he was being sexist by singling Ms Credlin out before the parliament during a debate over paid parental leave.

''I'm not going to apologise because that's my position,'' he said.

''Being elected to parliament carries a lot of different privileges in relation to raising certain issues.

''If people don't agree with me that’s fine.''

Mr Palmer said anyone who did not think Ms Credlin influenced ''the so-called ideas of the Liberal Party'' was ''naïve'', adding Ms Credlin was the ''top dog'', which he then quickly changed to ''top person''.

''I'm saying that I'm concerned that she has been able to exercise that influence on the PM and I believe as chief of staff, regardless of whether she is a woman or man, she exercises undue influence on government policy to the detriment of many of the elected members of Parliament,'' he said.

with Judith Ireland

smh.com.au