Malaysian immigration authorities have arrested 88 foreigners, including 64 Thais, in a crackdown on sex activities at three locations in Ipoh city.

The crackdown took place at a hotel and two entertainment venues suspected of offering sex services on Tuesday and Wednesday.

Perak's Immigration Department said the detainees were 78 women and 10 men, aged between 21 and 46. Of the detained, 64 were Thai, while the others were 13 Vietnamese, four Nepalis, three Indians, three Bangladeshis and one Sri Lankan.

An official said that the detainees faced multiple offences but did not provide details about the charges.

Ipoh, the state capital of Perak, is roughly halfway between the Thai border and Kuala Lumpur, about 300 kilometres from Sadao district in Songkhla.

The operation was the second major crackdown on prostitution involving Thais in less than a week. Last Friday, 22 Thai women were arrested in raids in the Malaysian capital and neighbouring Selangor state.