A multimillionaire Sydney financier is taking Northern Beaches Council to court in an attempt to stop it creating an off-leash dog area at Palm Beach.

The council decided at a meeting last week to proceed with a proposal to allow dogs at Station Beach in Palm Beach after dismissing claims it would cause environmental harm.

The Palm Beach Protection Group has launched legal proceedings in the Land and Environment Court to stop the trial to allow dogs off-leash on the beach.

Its Protect Palm Beach website claims that allowing off-leash dogs will threaten birdlife, increase the risk of unprovoked dog attacks on families and children and create traffic congestion and parking problems.