By Beh Lih Yi

JAKARTA (Thomson Reuters Foundation) - More than 90 percent of rape cases in Indonesia go unreported, highlighting the country's "deafening silence" around sexual violence as victims fear being blamed, organizers of a recent poll on the issue said on Monday.

The survey was carried out after the gang-rape and murder of a schoolgirl sparked public outrage.

It was published last week, on the same day the government pledged to set up a center to collect statistics on rape, seen by campaigners as an important step in helping prevent future sexual assaults.

Of the 25,213 respondents polled online, around 6.5 percent - or 1,636 people - said they had been raped and of these, 93 percent said they had not reported the crime, fearing repercussions.

Two-thirds of the rape survivors were under 18, according to the survey jointly conducted by Lentera Sintas Indonesia, a support group for victims of sexual violence, local magazine Magdalene and online petition website, Change.org.

Sophia Hage, campaign director at Lentera Sintas said the high percentage of rape cases going unreported was the "tip of the iceberg" in the country of 250 million people.

"It is a mirror of how sensitive the issue is and that people don't want to talk about it," Hage told the Thomson Reuters Foundation.

"The number one reason they are not speaking up is because of the social stigma and the victims are afraid to be blamed, so there is a deafening silence around the issue," she added.

Some 58 percent of the respondents - mostly women but also some men and transgender people - said they had experienced verbal sexual harassment. About 25 percent said they had been physically assaulted, including being groped and kissed.

The survey was carried out in June. Public figures and celebrities supported it, and some 75,000 people who had signed a petition on Change.org calling for stronger laws against sexual violence, were encouraged to take part.

The government-backed National Commission on Violence Against Women said in a statement the findings reflected people's low confidence in the country's law enforcement agencies in resolving sexual violence cases.

Indonesia's President Joko Widodo in May approved a law which allows the death penalty to be used as the maximum sentence against child rapists, after the rape and murder of a 14-year-old girl in April prompted a public uproar.

Offenders could also face chemical castration and be tagged with an electronic chip to track their movements under the law.

The government said last week it was planning to set up a data center by 2017 to collect statistics about sexual violence against women and children.

Women's groups say the lack of comprehensive data hampers education and prevention of sexual violence, and makes it harder to reflect the prevalence of the crime.

"We support the decision but the data center should be friendly to all survivors and the victims (to report cases)," Hage of Lentera Sintas said.

(Reporting by Beh Lih Yi @behlihyi, Editing by Alex Whiting; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, property rights and climate change. Visit http://news.trust.org)