HAIKOU, April 22 (Xinhua) -- Authorities in Hainan on Sunday imposed tougher restrictions on property purchasing that applies to the entire territory of the southern island province.

Starting from Sunday night, non-Hainan residents wishing to buy houses in newly restricted areas should provide proof of at least one family member paying taxes or for social security for 24 months or longer in Hainan.

Houses in the four "central ecological core areas" of Wuzhishan, Baoting, Qiongzhong and Baisha are only available for purchase by local residents. Those wishing to buy houses in Haikou, Sanya and Qionghai - areas already under restriction -- should provide proof of at least one family member paying taxes or for social security for 60 months in Hainan, government authorities said at a press conference.

A family whose household registration, or hukou, is transferred to Hainan after Sunday night, is allowed to buy one house only in the province, and proof is needed of at least one family member paying taxes or for social security for 24 months or longer in Hainan.

"City and county authorities should strengthen examination of house-purchasing qualifications to regulate property transactions," said Huo Juran, head of the Hainan Provincial Department of Housing and Urban-rural Development.

Home loans are also restricted. According to the government, non-Hainan residents buying houses or commercial property should pay at least 70 percent of the house price in the down payment. Residents or organizations are only allowed to sell their houses in five years after obtaining the property ownership certificates.