A residential building under construction is seen in Tongzhou, Aug 24, 2015.[Photo/IC]

Only 13 corporate apartments have been sold in Tongzhou in the past month, compared with 6,004 a month ago – a 99 percent drop.

As of June 5, 4,623 units were still on sale, covering more than 350,000 square meters in the Tongzhou district, a suburb in Beijing, according to data released by real estate company Centaline Property.

This change comes a month after Beijing extended its real estate restrictions in Tongzhou to cover business property and force out speculators.

Under the new policy, families without household registration in Beijing, unmarried Beijing residents who already own homes and families that own more than one home are among those no longer eligible to purchase corporate apartments in Tongzhou.

Those from outside Beijing will only be allowed to buy corporate apartments in the district if they have paid tax and social security payments in Beijing over five straight years.

The rules also stipulate that office space can only be sold to companies for business purposes.

Authorities previously introduced restrictions on residential property purchases in the district in August last year to curb speculation that sent home prices soaring.

The Tongzhou district, which is about 40 minutes' drive from the center of Beijing, was designated a subsidiary administrative center for Beijing municipality last year as part of measures to tackle overcrowding in the capital.

Xinhua contributed to this story.