The scale of the car upgrade that the Maranello team was able to deliver at Barcelona, despite new wind tunnel and CFD restrictions, prompted suggestions from other teams that the outfit could be exploiting the regulations.

One theory was that Ferrari was making use of extra wind tunnel time through its technical partnership with Haas, and there may even have been sharing of knowledge, personnel or parts.

With Ferrari's rivals making clear their frustrations to the FIA, Motorsport.com has learned that the governing body dispatched one of its senior technical inspectors to Maranello to investigate.

FIA visits Ferrari

The FIA's F1 Technical and Sporting Co-ordinator Marcin Budkowski, who was the former chief aerodynamicist of McLaren and used to work at Ferrari, was sent to Maranello to look closely at the Ferrari wind tunnel programme.

But after a detailed look, he was satisfied that Ferrari was operating within the rules and that its relationship with Haas was fully above board.

An FIA spokesman confirmed to Motorsport.com that the governing body had looked into how the relationship was working between Ferrari and Haas and has no cause for alarm.

"There is a unique arrangement between Ferrari and Haas, and we felt it necessary to check that things were being operated as agreed," he said.

"This was done in considerable detail during the week after the Spanish Grand Prix, and everything was satisfactory."

Ferrari and Haas separate

Although Ferrari and Haas are embarking on a close technical partnership for 2016, both teams are ensuring that they operate within the regulations.

Haas has been clear from the start that it will use as many technical parts as it can from Ferrari but will ensure it owns the IP for the parts it has to design itself.

A Ferrari spokesman confirmed that Haas was using the Maranello wind tunnel as part of its partnership, but rubbished talk that there was any sharing of knowledge, parts or staff.

"Ferrari has an agreement with Haas to provide it with a power unit and we also have a technical partnership," he told Motorsport.com

"As is allowed under the existing regulations, we are allowing them to use the wind tunnel in Maranello. But we do not have a shared wind tunnel programme.

"In aerodynamic terms we are two completely separate entities. The use of the wind tunnel is separate; there are separate models and parts. And also personnel are completely different. We do not share staff."

He added: "We were visited by Mr. Budkowski on behalf of the FIA. They have confirmed that everything is in order and we are well within the regulations."