The Coney Island boardwalk is about to resemble a sidewalk.

The city’s Design Commission yesterday approved a Parks Department plan to replace five blocks of the crumbling 89-year-old wooden boardwalk with a combination of cement blocks and plastic composite planks.

The approval angered some civic groups and beachgoers, who say it is a precursor to a larger Bloomberg administration plan to pave and lay plastic planks along the entire nearly three-mile walkway — except four blocks in the amusement district that would remain wood.

The plan calls for a 12-foot concrete pathway for emergency vehicles, flanked on each side by 19-foot-wide sections of planks.

The test area would run in the Brighton Beach section of the walkway from Coney Island Avenue to Brighton 15th Street.