Foreign Minister Penny Wong said she was worried about the lack of transparency surrounding the "live fire exercises", and would be raising her "concerns" with Beijing.

"We will be discussing this with the Chinese," she told national broadcaster ABC from Johannesburg, where she was attending a G20 meeting.

The drills sparked a warning from Australia's air safety agency, forcing some commercial flights to alter their course.

"As a precaution, we have advised airlines with flights planned in the area," government agency Airservices Australia said in a statement.

"We are also working together to coordinate advice to operators and pilots."

Australia's defence department has been monitoring the Chinese navy vessels -- a frigate, a cruiser and a supply tanker -- since they were spotted in international waters last week.

Although the ships are sailing in international waters, officials have described their presence as "unusual".

The ships were reportedly within 150 nautical miles (about 280 kilometres) of Australia's mainland earlier this week.