Waterfront homeowners can legally chop down trees blocking million-dollar harbour views in some of Sydney's most sought-after residential areas, under controversial vegetation clearing laws introduced for bushfire zones.

Residents have already started cutting down trees, including 100-year-old angophoras, at a rate of 10 a day in Pittwater, according to mayor Jacqueline Townsend.

"There are concerns there are going to be great big bald patches right up the escarpment," Ms Townsend said.

There are also fears the leafy suburbs of Mosman, Hornsby, Lane Cove and Beecroft, which have all been designated to be in bushfire zones, will be denuded by homeowners using the legislation to their own advantage.

The new 10/50 vegetation clearing code of practice from the Rural Fire Service, which came into effect this month, allows people across NSW living within 350 metres of designated bushfire-prone areas to clear trees on their property within 10 metres of a home without seeking approval. Shrubs can also be removed within 50 metres of a home. It makes no distinction between bushland and urban areas.