The Perth women say they have gambling problems and had rented the unit so as to be near the casino, but during the trip lost a significant amount of money, the court heard.

They apparently met some shady characters at the casino, and did some sex work to recover the cash.

Police raided the Reid unit on September 4 and warned the two Chinese nationals, aged 51 and 46, that it was illegal to work as a sex worker except in prescribed places, court documents say.

The apartment was dimly lit with red lighting, and there were condoms and lotions.

Police observed men approaching the apartment but turning away when they saw officers.

But the women say they did not understand the police, and when the officers returned the next day the pair had not stopped their activities.

When police arrived that day they found one of the women with a client and wearing lingerie, but nothing from the waist down.

The Perth women pleaded guilty to operating a brothel other than in a prescribed location.

A lawyer for the woman said they were both remorseful and felt ashamed of what they had done.

She said they were in Australia from China on "protection visas" but was unable to confirm whether they were permanent or temporary visas.

Special Magistrate Margaret Hunter convicted the women and fined them $1000 each.

She noted the point of the offence was to prevent brothels being operated in residential areas.