The mainland's oldest auction house held its first sale in Hong Kong on Sunday, underscoring intensified competition in the booming art market.

More than 300 collectors packed the auction hall at the one-day sale by China Guardian, which offered more than 300 Chinese paintings and calligraphy including works from renowned artists Zhang Daqian and Qi Baishi.

The sale, expected to fetch nearly $24 million, was the firm's first auction outside the mainland since it was set up in 1993.