A report on local government liabilities shows a lack of transparency over debt levels, Moody's Investors Service said on Thursday.

China's National Audit Office released a report last week on the debt of 36 local governments and their financing vehicles. "The NAO report highlighted increases in less transparent forms of borrowing and questions about local government debt repayment capabilities," said Debra Roane, vice-president and senior credit officer at Moody's in an email.

Because the report only covers a selected group of regional and local governments, its limited sampling makes it unclear how far-ranging these problems are, said Roane.

The report shows that for the 36 entities (15 provinces, three municipalities, 15 cities and three districts) the debt of local government financing vehicles and other entities associated with local government grew by a net 13 percent, or 440 billion yuan ($71.2 billion), from 2010 to 2012.

"Such a rise is not excessive for local governments. Given their strong revenue growth over the past two years, their overall debt burden, as measured by debt to revenue, has declined. However, debt increases for some local governments pose a risk," Roane said.

The debt-to-revenue ratio of nine provincial capital cities was more than 100 percent, according to the report, and one capital city's ratio was 189 percent, rising to 220 percent once the NAO included debt guaranteed by the city.