Sexual violence against women continues to be a major problem worldwide, a new study has found.

According to the findings, globally, one in 14 women - just over 7% - aged 15 years and older has been sexually assaulted by someone other than their partner at some point in their life.

International researchers decided to investigate this issue following several recent highly publicised rapes and murders of young women in India and South Africa.

"These cases are extremes of the wider phenomenon of sexual violence against women, but the true extent is poorly quantified. We did a systematic review to estimate prevalence," they said.

They looked at studies published on this issue between 1998 and 2011 and from this, identified 77 relevant ones, which involved women in 56 countries worldwide.

They found that 7.2% of women have been sexually assaulted by people other than their intimate partner at some stage in their lives. However this varies depending on where in the world they are.

Countries with the highest rates of sexual violence against women include those in sub-Saharan Africa, such as South Africa and Namibia, and New Zealand and Australia.

The lowest rates were reported in north Africa, the Middle East and south Asia.

Within Europe, sexual violence was more commonly reported in western and central Europe than eastern Europe.

However, the researchers emphasised that their findings ‘probably underestimate the true magnitude of the issue because of the stigma and blame attached to sexual violence'. This can lead to under-reporting and poor quality data.

"We found that sexual violence is a common experience for women worldwide, and in some regions is endemic, reaching more than 15% in four regions. However, regional variations need to be interpreted with caution because of differences in data availability and levels of disclosure," noted Prof Naeemah Abrahams of the South African Medical Research Council.

She added that the findings highlight the need for countries ‘to have their own population-based data on the levels of sexual violence by different perpetrators to improve understanding of the magnitude of the problem and the main risk factors, and to develop appropriate policies and responses, including primary prevention interventions and comprehensive services to treat victims of sexual assaults'.

Details of these findings are published in medical journal, The Lancet.