Famed fashion designer Oleg Cassini was scammed into buying a defective clothes dryer that nearly burned down his Oyster Bay Cove, LI, mansion, a suit says.

The late couturier replaced the faulty appliance after it caught fire in 2004, papers filed yesterday in Manhattan federal court charge.

Electrolux paid for the damage and said it corrected the defect, so Cassini bought the same model.

But in 2008 — two years after he died of a stroke — the replacement also ignited, wrecking several rooms, according to the suit, filed by Cassini’s company. Electrolux declined comment.