Two sex workers aged in their 20s and 30s, illegal immigrants, were arrested and released without charge after a late-night operation on Friday.

Detective Sergeant Andrew Raven, of the Warrnambool police crime operation unit, said the motel operators, a middle-aged man and woman, were expected to be interviewed on Monday.

He said police were still in the process of investigating possible prostitution and COVID-19 regulation breaches.

"We undertook surveillance operation at a Warrnambool motel for some time on Friday night," he said.

"There were a number of gentlemen who came and went from the motel.

"About 9pm we executed a search warrant. One man was found in a shower and a number of mobile phones and other potential evidence, such as client details, was seized."

Detective Sergeant Raven said the phones also contained potential evidence.

"We are still in the process of investigating potential charges in relation to sex work and COVID-19 breaches and will be seeking advice on Monday during further inquiries," he said.

Detective Senior Constable Ross Hatton is leading the investigation and anyone with information about prostitution operations is requested to contact the Warrnambool police station or Crime Stoppers on 1800 333 000.

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