A Reuters search on Wednesday of Airbnb listings in the city's centre yielded "zero" results for all of October. Listings were present as recently as Tuesday evening for periods including the congress dates of Oct. 18 to 31.

"Due to external circumstances, homes in certain areas in Beijing are unavailable through October 31," Airbnb said in an email to hosts reviewed by Reuters.

The move, mirrored by local rental firms, comes a week before the congress where President Xi Jinping is widely expected to consolidate power in a leadership reshuffle.

Such high-profile events are often accompanied by increased surveillance and online censorship. During the last Congress, in 2012, access to Alphabet Inc's Google search engine was cut off. Google services have since been blocked in China.

For this year's event, authorities have stepped up ID checks at metro stations and elsewhere in an effort to detain unregistered workers and others illegally residing in Beijing.

"EXTERNAL CIRCUMSTANCES"

Four Airbnb hosts in the capital told Reuters they had received notices from the U.S. firm late on Tuesday, which said properties in certain areas of the city would be removed from its website until the end of the month due to "external circumstances".

"Similar to action taken by other hospitality companies, Airbnb listings in certain areas in Beijing will be temporarily unavailable throughout October," the company said in a statement to Reuters.

Short-term rentals were also unavailable during the same period via local services Xiaozhu.com and Tujia.com. Neither firm responded to requests for comment.

Airbnb and other home-stay sites occupy a legal grey area in China, where tourists are required to register accommodation with local police using a passport or identification card. The requirement is harder to enforce with short-term rentals.

The Ministry of Public Security and Beijing's city police did not respond to faxed requests for comment.

"(The congress blackout) is a pain, but it's not for such a long time," said a 28-year-old press relations worker surnamed Liu, who rents out two flats on both Xiaozhu and Airbnb. "As long as (bookings) open again eventually, I don't mind."

(Reporting by Cate Cadell and Pei Li; Writing by Adam Jourdan; Editing by Christopher Cushing)

By Cate Cadell and Pei Li