A judge has ordered the US Food and Drug Administration to lift its ban on emergency contraception for women aged 16 and under.

Federal District Judge Edward Korman has directed the agency to remove the age restriction on Teva's now-genericised Plan B One-Step (levonorgestrel) emergency contraceptive within 30 days and allow the product on pharmacy shelves for all women. This challenges a decision taken by the US Health and Human Services Secretary Kathleen Sebelius two years ago to continue prescription-only access for women under 17, which actually overruled a recommendation from the FDA.

The morning-after pill has been hugely controversial across the Atlantic and it was only in 2005, after numerous delays, that the FDA allowed women 18 and older to have access to Plan B without a prescription. It was expanded to cover women aged 17 two years ago.

Judge Korman described Sec Sebelius' decision in 2011 as "arbitrary, capricious and unreasonable" and claimed that the FDA "has engaged in intolerable delays" which could be described as "an administrative agency filibuster".

It is not clear whether the US government plans to appeal but the judge's verdict has gone down well with women's health advocacy groups. Susannah Baruch, interim president of the Reproductive Health Technologies Project, said it represents "a long overdue victory for all women. Our decade-long struggle is finally over. Emergency contraception will now sit on store shelves allowing timely access to this important product used to prevent unintended pregnancy".

Urging Sec Sebelius and the agency "to move swiftly", she added that "for years, medical experts, including scientists at the FDA, American Academy of Pediatrics and American Congress of Obstetricians and Gynecologists, have agreed that emergency contraception is safe for over-the-counter use by women of all ages. Finally science won and the years of unnecessary politicisation of a safe and effective contraceptive are over".