A WOMAN accused of unlawfully performing oral sex on her ex-husband has no case to answer, an Adelaide court has been told.

The woman, 49, is charged with engaging in sexual intercourse without consent in August 2011 at an address in South Australia's Eyre Peninsula.

She appeared in the Adelaide Magistrate Court on Friday when her lawyer said the woman had no case to answer, noting it involved the woman's word against the complainant's.

Magistrate Simon Smart was told the complainant said he was awoken by his ex-wife performing fellatio on him.

The case was adjourned to September 6.