Severe thunderstorms in Sydney on Thursday killed at least one person and injured another, police said, with winds of 122 kmph (76 mph) lashing Australia's busiest airport, besides ripping down power lines and closing roads.

A man was killed and a woman passenger suffered critical injuries when a falling tree crushed their car in the city's west, which emergency services said took the initial brunt of the storm.

Photographs showed damaged shop fronts and roads left impassable by twisted metal and roofing panels. Authorities urged residents to stay indoors and keep away from windows.

"Substantial damage has been caused to a number of homes, cars and power lines," New South Wales state police said in a statement.

The fierce winds, rain and hail struck Sydney after a blistering day that drove temperatures to 39 degrees Celsius, the Bureau of Meteorology said, forcing disruptions at the city's international airport.

The storm had caused delays and diversions, Sydney Airport said in a Twitter message, urging passengers to check with individual airlines for details.

An airport spokeswoman could not immediately be reached for comment. - Reuters