BEIJING (Reuters) - Unmarried investors in the eastern Chinese city of Jinan must show proof that they're single if they want to buy a home, the official Xinhua news agency said on Monday, pointing to the lengths some cities are going to cool real estate markets.

Housing authorities in Jinan, the capital of Shandong province, announced earlier this month multiple measures aimed at curbing fast-rising home prices. Among the measures was a rule that home buyers would need to get a marital status certificate among other documents to qualify as a buyer.

But the Jinan government canceled the single status certificate last September, according to a document posted on the website of the Jinan Civil Affairs Bureau. That made it impossible for unmarried home buyers to prove their marital status, Xinhua reported.

Frustrated home buyers are calling for quicker responses from the government on the issue but staff with the local real estate trading center said they were "uncertain" when the problem would be resolved, Xinhua said.

Jinan was among more than two dozens Chinese cities that imposed policies to tame prices and reduce overheating during China's national holiday week. But real estate agents said that readily available, cheap mortgages and strong demand were likely to keep China's property market rising, even if restrictions dampen sales and prices over the short term.

Fueled by fears that restrictions would be put in place soon, home buyers in China's financial hub Shanghai rushed to divorce their partners to be able to invest in multiple homes before a new policy was rumored to take effect in September. Chinese police then detained seven property agents in Shanghai for spreading rumors.

Migrants in Shanghai who don't hold the Shanghai household registration are required to be married in order to qualify for home purchases, and they are only allowed to buy one house per family.

(Reporting by Yawen Chen and Ryan Woo)