Radio Australia reports that the human rights group's new approach overturns a previous neutral position on the debate over abortion and women's rights.
The new policy which forms part of Amnesty's global campaign to stop violence against women says that women who have been raped have the right to a safe abortion.
Widney Brown, Amnesty senior policy and campaigns director, told reporters that the organisation also viewed abortion as a right for women whose health was threatened by a pregnancy and that the group would call for the procedure to be decriminalised globally.
But Ms Brown said the policy stopped short of backing abortion as a "fundamental right" for women because that approach was not supported by international human rights laws.
She said the board of the London-based group agreed on the policy last month after two years of consultations involving experts and the organisations more than 2.2 million members.
The US Conference of Catholic Bishops also criticised the decision, saying Amnesty risked its "excellent record as a champion of human rights" if it abandoned its former neutral stance.
Amnesty also faces political opposition to the policy change as more than 70 members of a bipartisan US Congressional caucus against abortion urged Amnesty to oppose the surgical procedure.
Amnesty International joins abortion debate (Radio Australia, 10/5/07)
LINKS (not necessarily endorsed by Church Resources)
Amnesty International Australia
US Catholic bishops website
Canadian bishops warn Amnesty over abortion (CathNews, 21/7/06)
Amnesty, Vic ALP moves on abortion provoke Catholic ire (CathNews, 8/5/06)
11 May 2007