SHANGHAI, Jan 31 (Reuters) - China's government bonds extended gains on Wednesday, lifted by persistent investor expectations for imminent monetary easing to prop up growth in the world's second-largest economy.

Yields on the benchmark 10-year government bond, fell nearly 2 basis points to 2.4275%, the lowest since June 2002.

And yields on the ultra-long 30-year government bonds dropped further to a new historic low of 2.645%.

(Reporting by Shanghai Newsroom; Editing by Jacqueline Wong)