Chinese businesses remained worried about future development in the second quarter of 2013 amid overall optimism in Asian companies, according to the latest Thomson Reuters/INSEAD Asia Business Sentiment Survey published on Wednesday.

The survey, polling 91 top companies in the Asia-Pacific region, revealed that the Asia business sentiment index in Q2 climbed six points to 71, which is the highest of the past five quarters and also the third consecutive rise. A reading above 50 indicates a generally positive outlook.

But corporate sentiment in China, the world's second-largest economy, remained unchanged at a record-low of 50 for the second consecutive quarter, the survey revealed.

Although the uncertainties of the global economy remain the biggest commercial risk for most countries and industries, 44% of the companies involved reported a positive outlook, higher than the 30% proportion in the last quarter.

Among all the economies, companies in Australia and Indonesia are most positive about their business outlook, while the Indian business sentiment index has declined to a three-year low and the Thai index dropped to 42 from 60.

The survey showed that most sectors are more confident, with real estate, shipping and technology performing the best.