The deluge has led to rising floodwaters across parts of northern New South Wales. [Source: BBC]

Australian authorities have issued evacuation warnings for low-lying towns in northern New South Wales (NSW) as storms batter the nation’s east coast.

On Tuesday, emergency officials said they had fielded about 150 calls for help in the past 24 hours.

Huge swells pummelled the coasts of NSW and south-east Queensland on Monday, causing major erosion.

An already depleted beach at Byron Bay – a popular holiday spot – had all but disappeared, locals said.

Authorities said the storm had moved south on Tuesday, bringing the threat of flooding to inland NSW.