Leading Chinese real estate developers continued to reap rewards from the sustained housing demand in lower-tier cities during the first six months of the year, even as analysts warned of an earnings impact in the second half from policy tightening in more cities.

According to E-house, a Chinese property consultancy, during the first half of 2018, total sales of the nations' top 10 property developers, including Country Garden, Evergrande and Vanke, was around 2 trillion yuan ($301 billion), equivalent to daily sales of 10.8 billion yuan, or in other words a 28 percent growth on an annual basis.

Country Garden topped the list with total sales of 413.6 billion yuan during the period. The company's' major growth driver came from property sales in third- and fourth-tier cities.

Xie Yifeng, an analyst associated with a think tank under the Ministry of Housing and Urban-Rural Development, said despite disappointing sales in top-tier cities such as Beijing and Shanghai, the housing markets in second and other lower-tier cities saw a flurry of activity.

But with authorities slated to announce more measures to curb speculation and keep prices in check, Xie expects sales in the lower-tier cities to slow down.

By the end of June, seven central government agencies had said they would scrutinize property market transactions in 30 cities for the next six months.

"Destocking will become harder in lower-tier cities where the process is yet to be completed and which are witnessing more population net outflows," Xie said. "Once the scrutiny process becomes harder, the sales volume will slow."

Zhang Hongwei, an analyst with Tospur Real Estate Consulting, said: "The scrutiny will hurt the sales expectations of real estate companies and their expected cash inflows," he said. "The impact will be maximum in Central, West and Northeast China."

Xie expected the curbs to get tougher and the number of targeted cities for the same to increase in the next six months.

"In many cities, especially in lower-tier cities, there is still a huge gap between investment demand and the available property supply," he said. "The fundamental conflict between demand and supply exists and the curbs will become tougher."

Some cities like Shanghai, Beijing and Kunming already tightened curbs on property purchases from this month. For example, Kunming, the capital of Yunnan, has barred non-Yunnan buyers from purchasing more than one property in the city.

"The policy will shift from targeting individual buyers to companies to plug the loopholes in the property purchase regulations," he said.

"The limits on property price, home-purchase and bank loans will become tougher in more cities and the focus will shift from first- and second-tier cities to lower-tier ones," he said. "Housing prices in the targeted 30 cities increased too fast in the past, as the land price increased and the property supply slowed down."

The country's newly announced curbs were regarded one of the toughest actions so far.

Zhang Dawei, chief analyst at Centaline Property, said the curbs will help bring down the price and eliminate the disorder in the rental market.