SHANGHAI, July 4 (Reuters) - Bonds of Sino-Ocean Holding Group tumbled on Tuesday, after news that a bank was conducting due diligence on the Chinese builder triggered concerns of a possible debt restructuring.

Several Sino-Ocean bonds slumped more than 20% in Shanghai, triggering temporary trading suspensions required by the exchange, after Bloomberg News reported on Monday that China International Capital Corporation (CICC) had started due diligence on the company.

Wang Bo, Chief Investment Officer of Jurun Capital, said the likelihood of a debt restructuring is very high, given news of the due diligence.

Wang added that Sino-Ocean has a large amount of onshore bonds maturing this year, and the debt structure of the company is terrible.

UBS analysts also wrote in a note on Tuesday that Sino-ocean's bond price slump reflects higher expectations of a debt restructuring.

Yao Yu, founder of credit analysis firm Ratingdog, said that despite expectations that China Life Insurance Co may lend some help to Sino-Ocean, "the market is now broadly expecting payment extensions, just not sure when." (Reporting by Li Gu and Jason Xue in Shanghai, Tom Westbrook in Singapore; Editing by Kim Coghill)