About 48 women are raped in the Democratic Republic of the Congo every hour, a study has claimed.

The study, due to be published in the American Journal of Public Health in June, found sexual abuse was rampant not only in conflict areas but also in the home, with nearly one woman subjected to some form of sexual abuse every minute.

The DRC has been racked by war, with rapes widely documented in the conflict-hit east of the country. However, the study suggests the problem is bigger and more pervasive than previously thought, and goes further in documenting domestic sexual abuse.

It found 1,152 women are raped every day – a rate equal to 48 per hour. That rate is 26 times more than the previous estimate of 16,000 rapes reported in one year by the United Nations.

"Not only is sexual violence more generalised, but our findings suggest that future policies and programmes should focus on abuse within families," the study's researchers said.

The study, carried out by three public health researchers from the International Food Policy Research Institute at Stony Brook University in New York, and the World Bank, was partly financed by the US government and based on figures from a nationwide household survey of 3,436 Congolese women aged 15 to 49 in 2007.

The figures showed 12% of women had been raped at least once and 3% of women across the country were raped between 2006 and 2007. About 22% had also been forced by their partners to have sex or perform sexual acts against their will. The study also revealed alarming levels of sexual abuse in the capital, Kinshasa.

The UN has called the country the centre of rape as a weapon of war. Commentators have also described Congo as the worst place on Earth to be a woman.

Over the past 15 years, civilians have been drawn into the conflict, which has been driven by a weak government and rich mineral resources, often in remote, forest-covered areas.

The highest levels of rape were found in North Kivu, an eastern province ravaged by conflict, where nearly 7% of women were raped at least once between 2006 and 2007, according to the study.

Comprehensive statistics on rape in the DRC have been difficult to collate, although widespread anecdotal evidence has been collected on atrocities.

There have been many reports and witness accounts of the gang rape of young girls and elderly women by armed militia, and also accounts of men being raped. Because of the stigma of rape, many married women find themselves abandoned by their husbands.

"There are two big surprises in the study," said Anthony Gambino, a former mission director for the US Agency for International Development in the Congo.

"First, the magnitude of the problem – rates of rape that are much higher than seen elsewhere. And second, that these alarming, shockingly high rape statistics are found in western Congo as well as northern and eastern Congo."

Gambino said 40 years of "steady economic and political decline" may explain the high incidence of rape in the DRC.

While the authors have extrapolated their figures to show that as many as 1.8 million women out of the country's population of 70 million people have been raped, with up to 433,785 raped in a one-year period, some have urged more caution in the interpretation of the figures and their date.

Michael VanRooyen, the director of the Harvard Humanitarian Initiative, which has sent doctors to Congo to treat rape victims, said there were "some limitations in the methodology, such as the sampling methods and the sample sizes" of the new rape study.

But, he said, "the important message remains: that rape and sexual slavery have become amazingly commonplace in this region of the DRC and have defined this conflict as a war against women".

However, Michelle Hindin, an associate professor at Johns Hopkins Bloomberg School of Public Health, who specialises in gender-based violence, said that because the figures were collected during face-to-face interviews – where women could be less forthcoming – the figures could be much higher.

Margot Wallstrom, the UN special representative for sexual violence in conflict, said the figures in the study were higher than the UN's because they covered all sexual violence, including domestic and by known partners.

She said UN figures tended to be conservative because they had to be verified by the UN itself. "The number of reported violations are just the tip of the iceberg of actual incidents," she added.