The use of shark netting in NSW is a ''drastic measure'' that damages sea life and prevents few deaths, say marine ecologists.

After the second fatal shark attack within a week off the Australian coast, experts have called for an overhaul of the shark meshing program, which has been in place since 1937.

A researcher in marine biology at Southern Cross University, Daniel Bucher, said most people falsely believe that nets - which do not reach the seabed - act as a wall or barrier to protect swimmers.

''Quite a number of sharks can make it over or around them,'' Dr Bucher said. ''Nets are designed to reduce shark populations, which means a huge number must be caught to have any impact.''