McLaren's drivers have been warned of "serious consequences" if they do not co-operate with the F1 spying probe.
Ferrari currently trail McLaren by 11 points in the constructors' standings
Motorsport's governing body the FIA has written to Lewis Hamilton, Fernando Alonso and test driver Pedro de la Rosa asking for their full assistance.
It follows claims that "one or more" of the team's drivers may have been in possession of relevant material.
In the letter, FIA boss Max Mosley said co-operating would save them from any individual punishment.
"I can confirm that any information you may make available will not result in any proceedings against you under the International Sporting Code or F1 regulations," he pledged.
"However, in the event that it later comes to light that you have withheld any potentially relevant information, serious consequences could follow."
The FIA's World Motor Sport Council (WMSC) will meet in Paris on 13 September to discuss the "new evidence".
McLaren were found guilty by the WMSC of fraudulent conduct at an initial hearing on 26 July, namely being in possession of unauthorised documents belonging to Ferrari.
But they avoided sanctions as it could not be proved that the 780-page dossier found at the home of suspended McLaren chief designer Mike Coughlan had been used by the Woking-based team.
If the new allegations are found to be true, it is possible McLaren could be expelled from this year's championship, so wrecking Hamilton and Alonso's title hopes.
It has been reported that the "new evidence" relates to an e-mail exchange between Alonso and de la Rosa.
But when asked ahead of this weekend's Italian Grand Prix whether that was the case, Alonso said: "This is a lie.
"I am going to try to win the last five races of the season and of the other themes I am not going to talk about because it does not concern me."
McLaren said in a statement that they staying silent on the matter ahead of the WMSC hearing.
"The team and our drivers (will) make no further comment, and we kindly ask the media to understand this position."