The FIA are reportedly set to launch an investigation into the 2025 McLaren and Ferrari cars after receiving a complaint from rivals Red Bull.
The new 2025 F1 season begins next Sunday with the Australian Grand Prix at Albert Park.
All 10 teams have completed three days of testing at the Bahrain International Circuit, which took place earlier this week.
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Williams driver Carlos Sainz posted the fastest lap time over the three days, with Ferrari's Lewis Hamilton in second place.
Hamilton will kick off 2025 in search of a record-breaking eighth world championship, having left Mercedes at the end of 2024.
Ferrari will be competing with Red Bull, Hamilton's former team Mercedes and holders McLaren to win this season's Constructors' Championship.
But according to Italian outlet FUnoAnalisiTecnica, Red Bull have prepared an early official complaint over the Ferrari and McLaren cars.
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It is claimed that Red Bull believe both teams are 'in breach of the regulations' over their rear wing designs for 2025.
Technical director Pierre Wache is said to have approached the stewards with his concerns during testing, but that the FIA have so far 'turned down' the complaint - which has prompted the official file.
The report adds that FIA officials are now expected to visit the two teams' bases at Maranello and Woking respectively before the Australian Grand Prix. Ferrari, for their part, are said to 'reject' the accusations.
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Last season, Red Bull complained about McLaren on several occasions during the latter part of their fight for the Constructors' Championship.
McLaren offered to make minor changes to the design of the DRS device on their rear wing after FIA discussions following the Azerbaijan Grand Prix. It is unclear whether Red Bull's most recent complaint is in relation to that or a separate issue.
The 2025 season will be the final year of the current FIA development regulations, with a raft of changes to brought in for the 2026 season onwards.
SPORTbible have contacted Scuderia Ferrari HP, McLaren and the FIA for comment.
Ryan Smart