'Bomb cyclone' pummels Sydney with heavy rains, winds

A ‘bomb cyclone’ has lashed Australia's most populous state with heavy rain and strong winds, forcing airlines to cancel domestic flights and prompting evacuation warnings in coastal communities.

Authorities on Tuesday warned that parts of New South Wales could also expect the wild weather to worsen in the next 24 hours, with up to 9.8 inches of rain and winds up to 125 kmph predicted.

Emergency Services Minister Jihad Dib said the size of the system was ‘enormous’.

"It may seem pretty bad but the terrible thing is the situation is going to worsen over the course of the next 24 hours," he told a news conference on Tuesday afternoon.

Residents living along areas vulnerable to coastal erosion have been told to leave their homes with minor flood warnings also in place for several communities along the state's Mid North Coast.

Qantas Airways cancelled at least 11 domestic flights operating from Sydney and Virgin Australia cancelled 12, the Sydney Airport website showed. No international flights have been affected.

"Some services on Virgin Australia's network have been impacted by adverse weather in Sydney and Newcastle today," a Virgin Australia spokesperson said.

Australia’s weather bureau said a ‘bomb cyclone’, or ‘bombogenesis’, was a low-pressure system that formed quickly and caused pressure to drop significantly within a short period of time.

The weather system is expected to shift offshore into the Tasman Sea on Wednesday and ease by Thursday, the bureau said.

"Damaging winds and large seas will continue across much of the coast through Wednesday, with warnings expected to continue," Senior Meteorologist Helen Reid said. "Conditions will continue to ease into Friday with only very light isolated showers lingering about the east coast by the end of the week."