At least one person has been killed and another injured in severe thunderstorms battering the Australian city of Sydney, police say.

According to the police report on Thursday, a man was killed and a 60-year-old woman sustained critical injuries in the western part of the city.

"A large tree appears to have fallen across the road on top a vehicle, which tragically has ended in the death of one person," Inspector Murray Traynor said. "Also a female patient has been transported to Westmead Hospital with pelvic and abdominal injuries, as well as lower limb injuries."

Fierce winds of 122 kmph (76 mph) forced authorities to ask residents to stay indoors and keep away from windows.

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

Reports say almost 80,000 homes and business are without power as a result of storm damage.

The storm along with rain and hail also caused disruptions at the city's international airport.

The Bureau of Meteorology (BoM) in Sydney had earlier issued a severe weather warning for parts of New South Wales, including Sydney.