A delegation of US nuns rapped for defying Church doctrine, including teachings against homosexuality and contraception, were at the Vatican Tuesday to explain their case.

A Vatican report has accused members of the Leadership Conference of Women Religious (LCWR), which represents around 80 percent of the 45 000 nuns in the United States, of "corporate dissent" with the Church's teachings against homosexuality, and claimed it was pursuing "radical feminist themes."

The three-year inquiry by the Congregation for the Doctrine of the Faith, which oversees Roman Catholic doctrine, criticised the LCWR in particular for taking liberal stances on contraception, homosexuality and female priests.

Nothing has emerged so far on Tuesday's meeting at the Vatican.

But the nuns have already rejected the report, saying that they have not violated any teaching.

They have also found fault with the way the report was carried out, complaining that it was shrouded in secrecy.

The US church has been increasingly involved in social work and education, with nuns who have taken on areas previously reserved for men in the institution, including marriage counselling or psychological help.

Some members of the US church have also spoken out against what they view to be extreme rigidity on questions surrounding contraception and homosexuality.