A brothel madam who made money from underage girls working in the sex industry has been warned to prepare herself for prison. But her lawyer says "extremely unusual factors" need to be considered.

Company director Anna Anastazja Horlor, 59, yesterday pleaded guilty in the Christchurch District Court to two charges of receiving earnings from commercial sexual services provided by two girls, aged 16 and 17.

A person must be at least 18 to work in the sex industry.

Horlor was to have faced trial on two charges relating to exploitation of the girls, but decided instead to plead guilty at a preliminary hearing yesterday.

In July 2008, a depositions hearing heard the girls had been working at Christchurch's Atami Bathhouse.

A mother told the hearing how she saw six or seven women on stage dancing and performing sex acts. She persuaded her daughter, 16, to leave.

Judge Michael Radford told Horlor yesterday she should be ready to go to prison when sentenced.

Outside court, Horlor's lawyer, Hamish Evans, said they did not accept the judge's indication of a sentence. "There are some extremely unusual factors."

- staff reporter, NZPA