Arizona's top court revived a law dating to 1864 on Tuesday that bans abortion in virtual all instances, another setback for reproductive rights in a state where the procedure was already barred starting at 15 weeks of pregnancy.

The Arizona Supreme Court ruled 4-2 in favour of an anti-abortion obstetrician and a county prosecutor who took up defence of the law after the state's Democratic attorney general had declined to so.

Justice John Lopez, who like all of the court's members was appointed by a Republican governor, wrote that to date, the state's legislature "has never affirmatively created a right to, or independently authorised, elective abortion."

"We defer, as we are constitutionally obligated to do, to the legislature’s judgment, which is accountable to, and thus reflects, the mutable will of our citizens," Lopez wrote.

The fight over abortion access in Arizona is far from over. A group of abortion rights advocates last week said it gathered enough signatures to put before voters in November a ballot measure that would enshrine in the state's constitution a right to an abortion until fetal viability.

Arizona Attorney General Kris Mayes, a Democrat, in a statement called the ruling "unconscionable and an affront to freedom," and stressed that she would not while in her position prosecute any doctor or woman under the "draconian law."

"Today's decision to reimpose a law from a time when Arizona wasn't a state, the Civil War was raging, and women couldn't even vote will go down in history as a stain on our state," she said.

The ruling marked the latest legal setback in days for abortion rights, following a ruling last week by the Florida Supreme Court that cleared the way for a Republican-backed law banning abortion after six weeks of pregnancy to take effect. (Reuters)