Utah's Republican Gov. Gary Herbert has thrown his support to a proposal to administer anaesthesia to unborn babies during an abortion procedure, calling it the "most humane" way to end a human life.

"You know, abortion is a very emotional issue," Herbert told reporters, according to KSL. "Rather than get into the abortion debate, I guess the question is: If we're going to have abortion, what is the most humane way to do it?"

He said he doesn't know at what point a foetus may feel pain.

"Foetuses have a heartbeat after about five weeks. And the idea of just being callous about that should cause all of humanity's concern," said Herbert, who is opposed to abortion.

He added that if foetuses feel pain, then he is in favour of a bill being crafted by Republican state Sen. Curt Bramble to "eliminate that discomfort." He added that he will review his bill once it's drafted.

Bramble told KSL Newsradio that the bill intends to protect from "the pain inflicted at the time that the unborn child's life is taken."

Montana lawmakers passed a similar bill last year requiring foetal anaesthesia for surgeries, including abortion after 20 weeks of gestation. However, this was vetoed by Democratic Gov. Steve Bullock.

About a dozen states have approved a ban on abortion after 20 weeks to protect "unborn children who are capable of feeling pain," according to the National Right to Life Committee.

Planned Parenthood's Karrie Galloway, CEO of the abortion provider in Utah, is opposing the bill, saying "obviously, he [Herbert] wants to insert his political opinion in a private decision between a woman and her physician," the Associated Press reported.

Nearly 60 million children have been aborted in America since the 1973 U.S. Supreme Court decision of Roe v. Wade, the Christian News Network reported.