Shanghai's housing prices tumbled 4.5 percent in a single day last week amid apparent efforts by the central and local governments to rein in the city’s skyrocketing market.

Average home prices went down from 8,153 yuan (US$984.66) per square meter April 6 to 7,785 yuan per square meter April 7, a day after the Shanghai city government issued a new rule to restrict sales of mortgaged property in the city, the Beijing Times reported.

The new regulation, which took effect April 5, makes homeowners pay off their entire mortgages before they can sell the property. Property owners with mortgages can still sell if they find a buyer willing to put down the entire balance of the mortgage as a downpayment to pay off the loan.

In another new measure, the Shanghai city government is extending the waiting period between the sale and transfer of ownership for property to 28 days from the previous seven.

An official at the Shanghai housing and land administration bureau said the policy was aimed at preventing speculative property transactions, the main engine behind the double-digit increases in average real estate prices in Shanghai in the past few years.

Housing prices in Shanghai surged 18 percent in the past year, according to the city government’s property index. Personal housing loans in the city in the first two months of this year rose 64 percent from a year earlier. Loans to developers increased 41 percent and three-quarters of new bank loans in Shanghai last year related to property.

China began tightening access to credit for property development more than a year ago and the People’s Bank of China, the central bank, has raised the interest rate charged on mortgage loans of more than five years to 6.12 percent from 5.31 percent.