Both Haas Formula 1 cars are at risk of exclusion from the results of Monaco Grand Prix qualifying after an element of non-compliance was found on both their rear wings.

Nico Hulkenberg qualified 12th for Sunday's race, with team-mate Kevin Magnussen three places behind.

But both are now at risk of losing those positions and going to the back of the grid - which would make the weekend an effective write-off.

A report from the FIA's F1 technical delegate Jo Bauer after qualifying stated that a check of "the uppermost rear wing element adjustable positions" turned up an area of non-compliance.

"The LHS [left-hand side] and RHS [right-hand side] outermost area of the adjustable elements [of the rear wings] were exceeding the maximum allowed 85mm on both cars".

This contravenes Article 3.10.10 h) of the technical regulation, which concerns the drag reduction system and states that "the distance [at the Y plane] between the two sections of the rear wing profiles at their closest position must lie between 10mm and 85mm".

A breach of the technical regulations normally equates to the removal of the offending car from the classification.

The matter has been referred to the stewards.

Three years ago, Lewis Hamilton famously had his Brazilian Grand Prix qualifying result excised due to the DRS gap on his Mercedes being more than 85mm when it activated.

Haas introduced a new rear wing this weekend in order to maximise downforce, which is naturally at a premium in Monaco.

The team said the new spec of wing "pushes the geometry to the limit of possible achievable load inside the allowed rule box".

If it cannot make the wings rule-compliant, it would have to switch to a different spec - which would be in breach of parc ferme and would require both cars to start from the pitlane, although the team's weekend is already materially over if its qualifying results are nullified.