Whitmarsh suspects Red Bull technology
McLaren team principal Martin Whitmarsh says Red Bull's pace-setting form is being aided by a system he believed was against Formula 1's rules.
Red Bull have been untouchable in qualifying this season with Sebastian Vettel taking pole for both races.
"There's evidence there are ride-height control systems which many people thought weren't permissible," he said.
Red Bull team boss Christian Horner said he could "absolutely guarantee" their car had no such system.
F1 has banned refuelling this year so cars have to start the race with enough fuel to complete the entire distance.
It looks like Red Bull and some other cars are able to run lower in qualifying than you would expect if they're then going to fill the car with fuel afterwards
McLaren team principal
That equates to about 160kg of fuel, whereas to extract maximum performance in qualifying the cars run only enough fuel to allow them to get in and out of the pits and do their qualifying lap.
In theory, the lower fuel load in qualifying should mean that the car runs higher off the ground than it does at the start of the race - and therefore too high for optimum performance.
F1 teams run their cars as close to the ground as possible because the lower they are the more aerodynamic downforce they can create and the faster they will go around corners.
So if a team could find a way of keeping its car low in qualifying despite the low fuel load, it would give them a significant advantage.
Vettel qualified 0.116secs ahead of team-mate Mark Webber and the only car able to get close to them was Fernando Alonso's Ferrari, which was 0.192secs adrift of Vettel. McLaren driver Jenson Button, in fourth, was 0.756secs off pole.
"It looks like Red Bull and some other cars are able to run lower in qualifying than you would expect if they're then going to fill the car with fuel afterwards," Whitmarsh said.
"As you can imagine, we're working quite hard on those systems now.
Red Bull are in a league of their own in F1 qualifying
"The original rulings suggested such systems wouldn't be allowed on cars but we're seeing some cars which seem to have them.
"We've got to have them fitted as soon as we can - hopefully by China (the fourth race of the season on 18 April) we'll have something on the car."
It is not known how any such system - if it exists - would work, although insiders suspect it may be some form of ratchet that prevents the car's suspension rising beyond a certain point.
Whitmarsh's remarks come after two other incidents in which leading McLaren employees have made controversial remarks about Red Bull.
McLaren Group chairman Ron Dennis said he suspected the problem that cost Vettel the lead in the Bahrain Grand Prix was a shortage of fuel, not a broken spark-plug that Red Bull claimed.
And Lewis Hamilton said in the run-up to the Australian Grand Prix that he thought Red Bull driver Mark Webber was considering retiring at the end of the season.
Horner and Webber have strenuously denied both claims.
Horner said on Saturday: "There are funny things happening at McLaren - Lewis managing Mark, Ron reckoning we have a fuel problem and now Martin reckons we have a ride-height control."
Mercedes team boss Ross Brawn said after qualifying that he thought governing body the FIA should issue a rules clarification on the subject of ride-height controls to end the suspicion and speculation.