Canberra, Jan 14 (IANS): Beaches on Australia's New South Wales coast remained closed for the fifth day after sharks were sighted in Newcastle.

Four sharks were reportedly spotted at beaches across New South wales Tuesday.

The remains of a dolphin, believed to have been killed by a shark, were also found, Xinhua reported.

Andrew Fox, from the Fox Shark Research Foundation, refused to disclose information regarding tagged sharks, saying the details will be used to support state governments' catch-and-kill policies particularly in Western Australia, to cull potentially dangerous sharks.

He has been monitoring the movements of several species throughout Australia.

Three sharks were also sighted three days back and the administration is trying to find out the reasons behind frequent shark-sightings in the area.

Earlier, a police boat also suffered damage after it was attacked by a shark with its tail, reports said.

Australian beaches are a popular tourist attraction and are often visited by a large number of people from across the world.