The sport's governing body, the International Automobile Federation (FIA), published the 2013 technical regulations on Thursday which authorise the use of special fairings to restore the sleek, flowing looks of previous years.
Article 3.7.9 refers to "an optional, single piece, non-structural fairing of prescribed laminate" that can be used to smooth the transition between the car's low nose and high chassis.
They will not affect the car's aerodynamics and teams are not obliged to use them.
McLaren technical director Paddy Lowe said at the Italian Grand Prix that such 'modesty panels' could be fitted over existing structures without requiring more substantial and costly changes.
McLaren, whose car has won five of the 14 races so far this season, are alone among the top teams to have a flowing nose rather than the stepped solution adopted by others in response to regulations aimed at protecting the drivers from frontal impacts.
Ferrari's 2012 car, which has taken championship leader Fernando Alonso to three wins, was seen as the ugliest in years to emerge from the Maranello factory when it was unveiled.