The office market has seen declines in investment, sales and demand in the third quarter of 2018, ushering the commercial office market into a new phase of adjustment, a report from Haozu.com said.

"Structural deleveraging is the major factor influencing current economic performance," said Kuang Jianfeng, the website's co-founder.

According to the report, the overall property investment growth rate has remained stable, while investment growth rates in the commercial office market have declined to 11 percent due to increases in land purchase costs.

The overall supply in the commercial office sector has continued to decline with new completed areas dropping by 14 percent in the third quarter of 2018, the report said.

"The IT and internet industry has remained the biggest client in the office rental market in first-tier cities, accounting for 40 percent," Kuang said. "Industries including trade, service, finance and entertainment are also major clients."

Vacant rental office area has grown, due to an increase in supply and surrender of leases, increasing the area available for rent by 50 percent compared with last year, the report said.

"In the future, new supply in the commercial office market will be slowing down," Kuang said. "The government will continue to introduce policies to optimize industrial structure and release new demand."

Fan Hang contributed to this story.