Nepal Police officer Bharat Bohora said they have confiscated documents and laptops and arrested one Chinese national and 20 others during the operation.
The Chinese national had rented a house in Kathmandu to operate the call centres.
The police have suspected that the Chinese nationals could be involved in cyber crime and running other illegal activities.
On Sunday, a police team conducted similar kind of raids in Butwal city near the India-Nepal border where Chinese and Indian nationals were caught running an illegal call centre.
As many as 120 people were arrested in Butwale.
On June 30, police raided a company run by a Chinese national in Pokhara.
According to sources, the police are interrogating three Chinese and 75 Nepali nationals working in the company.
The Nepal Police on December 23, 2019, arrested 122 Chinese nationals from all over the Kathmandu Valley.
The operation, the largest one against any foreign nationals in Nepal’s history, apparently continues and at least 800 more Chinese nationals are being watched currently.
Later the Nepal government handed them to Chinese authorities.
After the arrest, a spokesman for China’s Ministry of Foreign Affairs had said that the cases were related to cross-border cyber fraud activities, and that the investigations were ongoing.