SHANGHAI: Chinese shares closed lower on Wednesday, hurt by weakness in tech-heavy startup board ChiNext, after investors booked profits after two consecutive sessions of sharp gains.

The blue-chip CSI300 index ended down 1.2% at 4,706.13 and the Shanghai Composite index shed 1.3% to close at 3,329.74.

ChiNext dropped 2.1%, while the STAR50 index was down 3.1%.

Fourteen out of 18 companies that debuted on ChiNext on Monday, as part of a historic reform that relaxed listing requirements and trading rules of Shenzhen stock bourse, posted huge losses.

Ningbo KBE Electrical Technology Co Ltd was the worst performer, losing 20.5%. Other drags included AnHui Jinchun Nonwoven Co Ltd, which dropped 17.9% and Contec Medical Systems Co Ltd, down 17.4%.

New ChiNext shares can now trade without daily cap for the first five trading days, and can trade up to 20% in sessions afterwards. It allowed shares to rise or fall up to 10% previously.

The market should be quite volatile this week following the listing of the first batch of tech companies on ChiNext, some market watchers said, adding that the reform should reduce speculative behaviour in the mid- to long-term, and investors would then focus more on fundamentals.

Asset managers are racing to launch index funds tracking China's top technology companies, capitalising on investor fervour stirred by Sino-US tensions, and fuelled by Ant Group's blockbuster listing.