BEIJING (Reuters) - China's debt risks are under control given its high savings rate, but steps are needed to tackle exceptionally high corporate liabilities, an influential government economist said on Wednesday.

"The possibility of having a debt crisis in China is small," Li Yang from the Chinese Academy of Social Sciences (CASS), a top government think-tank, told a news conference.

"China is a country with a high savings rate and its debt problem is mostly internal, which is totally different from countries with low savings," Li said.

Global investors are increasingly worried about mounting debt in China, with continued efforts by authorities to stimulate the economy threatening to amplify the problem.

Policymakers in Beijing also appear more aware of the risks.

China may suffer from a financial crisis and economic recession if the government relies too much on debt-fuelled stimulus, the official People's Daily quoted an "authoritative person" as saying in May.

China's total debts amounted to 168.5 trillion yuan ($25.6 trillion) at the end of 2015, equivalent to 249 percent of gross domestic product, according to Li's estimates.

China's savings rate is close to 50 percent and the government still has sizeable assets at hands to deal with debt problems. He estimated that China's net sovereign assets at 103.3 trillion yuan.

The debt-to-GDP ratio of China's corporate sector was estimated at 131 percent in 2015, and as high as 156 percent if liabilities of local government financing vehicles were included, Li said.

"If there are problems in corporate debt, banks will have problems immediately. If banks have problems, government finances will have problems as banks are owned by the state," he said.

The International Monetary Fund called on Beijing this week to act quickly to tackle mounting corporate debt which it estimates has swelled to about 145 percent of gross domestic product.

China's government debt was equivalent to 39.4 percent of GDP in 2015, and the ratio was as high as 56.8 percent based on a broader definition, Li said, without elaborating.

Li said China should set up a unified task force to deal with its debt issues and the government should tread warily in allowing firms to convert debt into equity.

(Reporting by Kevin Yao; Editing by Kim Coghill)