SYDNEY, June 7 (Xinhua) -- Four people have died while three are still missing from the massive storm front that hit Australia' s east coast as major inland floods, giant waves and unusually high tides continue to wreak havoc.

The waves and a massive king tide have eroded 50 meters of beach along a key stretch of Sydney's Northern Beaches, according to the University of New South Wales' (UNSW) Water Research Laboratory, risking a number of multi-million dollar waterfront properties falling into the sea.

While most of the damage occurred on Saturday and Sunday nights,  Australia's weather bureau is forecasting another 'king tide' on Tuesday night, potentially causing more erosion to the coastline as wave heights continue to remain high.

"The threat of coastal erosion continues to ease as wave heights gradually reduce along the coast. There remains a low-level threat of some residual erosion, given the forecast tides being at or near the highest of the year," Australia's Bureau of Meteorology said.

Residents from seven of the waterfront properties and an apartment block were evacuated on Sunday, and have not been allowed to return until structural engineers conduct safety inspections.

Local residents are also anxious as the Insurance Council of Australia (ICA) said on Tuesday that those properties are unlikely to be insured given most policies don't cover "actions of the sea" which include king tides and coastal erosion.

"Ninety-three percent of all new home insurance policies purchased in Australia now include cover for flooding (under the standard definition), but neither actions of the sea nor the effects of gradual sea level rise are considered to be flooding for insurance purposes," ICA spokesman Campbell Fuller said.

The ICA said insurers have received more than 11,150 claims worth an estimated 38 million Australian dollars from the storms, however it's expected that the figure will rise over the coming days.