The work started last week and is expected to take about a month.

This part of the foreshore was severely eroded by storms and high tides last April, as were many other Port Phillip Bay beaches in the region.

The work is being carried out by Beaumaris-based Australian Project Solutions for the Department of Sustainability and Environment.

The contractor is using sandbags invented by Geofabrics Australasia of Braeside, a company involved in erosion control around the world.

Neil Taylor of Geofabrics said the sandbags, known as Elcorock, were "robust geotextile containers containing local sand that last 15 years or more".

"They will form a vandal-proof seawall of six levels, three below low tide and three above," he said.

Revegetation of native plants would occur naturally in and around the bags, he said.

Fifty sandbags will be installed at Portsea pier later this week to try and stop massive erosion that has removed tonnes of sand from the popular beach.