SYDNEY, July 1 (Xinhua) -- Residents of waterfront homes north of Sydney have been told to evacuate and thousands of people have been left without power amid dangerous storm activity on Tuesday.

The storm system swept across Australia's east coast on Tuesday morning, bringing heavy rainfall and damaging winds that prompted emergency warnings for almost the entire coast of the state of New South Wales (NSW), including Sydney.

Authorities on Tuesday afternoon advised residents of waterfront properties on the NSW Central Coast, 65 km north of Sydney, to evacuate due to the threat posed by dangerous waves that could damage buildings.

Energy distributor Ausgrid said that as of 5 p.m. local time on Tuesday, about 21,000 customers in Sydney, the Central Coast and the neighboring Hunter region were without power after the storm brought down power lines.

Speaking at a press conference, NSW Emergency Services Minister Jihad Dib said that rains and winds were expected to intensify through Tuesday night and into Wednesday.

"The situation is going to worsen over the course of the next 24 hours," he said.

Dib urged people to stay up to date with the latest emergency warnings, to avoid unnecessary travel and to not drive through floodwaters.

An updated severe weather warning issued by the Bureau of Meteorology shortly before 5 p.m. said that heavy rainfall that could cause dangerous flash flooding is expected to develop in the Illawarra region south of Sydney later on Tuesday night.

The State Emergency Service (SES) in NSW has advised residents of an 80-km stretch of coast between the towns of Jervis Bay and Batemans Bay south of Sydney to stay indoors.

NSW SES deputy commissioner Debbie Platz told Australian Broadcasting Corporation radio that fallen trees have been reported in Sydney and the Central Coast.

The SES has deployed more than 1,000 volunteers to aid emergency services personnel in responding to calls for assistance.