UNITED Nations peacekeepers have abandoned at least 20 babies fathered with poverty-stricken Timorese women.

A UN investigation has also uncovered a culture of cover-up, in which babies born to peacekeepers and sex crimes committed by UN staff in the past seven years have been kept secret because of a "fear of shame and embarrassment' in the deeply religious country.

The findings will shock the UN bureaucracy as it prepares to boost by thousands its peacekeeping force in East Timor.

A report on the investigation, obtained by The Age, recommends that a policy of zero tolerance of sexual misconduct be enforced on UN staff sent to help rebuild the country after two months of violence.

UN peacekeepers in East Timor have previously been accused of offences including child sex abuse, bestiality, and coercing women and children into prostitution. No one has ever been charged.

But the report reveals for the first time that babies born to UN peacekeepers have been abandoned without financial support.

It also makes clear that the births of these children, and other instances of sexual misconduct by UN personnel, are likely to have been significantly under-reported.

The report says that the Timorese mothers of the babies fathered by peacekeepers have been stigmatised and, in some cases, ostracised by their communities. It also found that efforts within the UN to organise help for the women have failed.

In the mountainous coffee growing district of Ermera, soldiers have left behind seven young children after earlier promising to marry their mothers, the report says. In the district of Bobonaro, four babies were allegedly fathered by two UN police and two civilian staff.

A dowry was apparently paid to one family. But in most cases, the mother's family has been left to support the children.

The report was written by Sofi Ospina, an anthropologist commissioned by the UN to investigate the gender-related impact on East Timor of having 18,000 uniformed and civilian UN personnel from 113 nations in the country after UN operations began in 1999.

It comes as Secretary-General Kofi Annan prepares a report for the UN Security Council on the composition of a new mission for East Timor when the current one expires next month.

Ian Martin, a special UN envoy, has recommended the Security Council send police units backed by a rapid response force. He also recommends a military presence at least until after elections scheduled for May, and UN advisers to help organise the vote.