SYDNEY (REUTERS) - Australia is investigating a suspected espionage case at the country's top scientific organisation, with a Chinese national being probed for allegedly accessing sensitive data, Fairfax Media reported on Wednesday.

The case may further test relations with China after the Australian foreign minister called in the Chinese ambassador to Canberra last week to ask for an explanation for a new air defence zone unilaterally set up by China in disputed international waters.

Australian federal police and security agencies are investigating a Chinese national, who until last week worked at the Commonwealth Science and Industrial Research Organisation, Fairfax reported.

"CSIRO became aware of a matter involving an employee suspected of unauthorised use of CSIRO computers," the organisation's spokesman Huw Morgan told Reuters in an email.

"We consider this a very serious matter and have referred it to the Australian Federal Police. It is not appropriate for us to release any further details at this time," he said.

Police said an investigation was underway but that no one had been arrested.

The Chinese man under investigation is a post-doctoral student at the highly sensitive nanotechnology laboratory in Melbourne, Fairfax reported, without naming him.

The CSIRO's nanotechnology area works closely with Australia's Defence Science and Technology Organisation.