China has ordered local authorities to implement existing property tightening measures or face punishment, the official Xinhua news agency said on Sunday, reflecting Beijing's resolve to tame sky-high property prices.

China will also quicken the pace of its experiment with property tax, Xinhua added, citing a report from the National Development and Reform Commission, the top economic planner.

But the report, which will be submitted to the country's parliament that opens its annual session on March 5, did not spell out details or a time frame for expanding the property tax.

The cities of Shanghai and Chongqing began experimenting with the country's first-ever tax on home ownership in late January.

The NDRC also ordered commercial banks to carry out differentiated mortgage rate policies and said it would slap heavy penalties on real estate developers if they are found hoarding land or delaying the sales of new housing units.

The commission urged local governments in cities experiencing fast-rising property prices to increase the supply of land that is used to build mid- to small-sized apartments.

Premier Wen Jiabao pledged on Sunday that the government will build 36 million units of affordable housing by 2015, with the first 10 million to be constructed this year.

Beijing has taken a slew of measures since 2009 to rein in China's red-hot property market, including raising down payments and mortgage rates, and limiting the number of homes that one family can buy.