Shanghai authorities placed local property tycoon Chau Ching-ngai under house arrest more than a week ago on suspicion of financial crimes, ranging from illegal fund-raising to tax fraud, a mainland newspaper said yesterday.

The China Securities News said state auditors raided Nongkai Development Group, Mr Chau's flagship company, on Monday to investigate financial irregularities by a number of Mr Chau's companies. Police declined to comment.

Following news reports, the Shanghai Stock Exchange said it had suspended from trading all companies with links to Mr Chau.