Red Bull have threatened to launch more protests against Ferrari next year after labelling the FIA's penalty in Abu Dhabi a "joke".

The final races of 2019 saw the Italian team's performance dip after the governing body issued several technical directives on the engine regulations following requests for clarification from Red Bull and Mercedes, though team boss Mattia Binotto denied any link.

At Yas Marina, however, Ferrari were fined 50k Euros after a fuel discrepancy on Charles Leclerc's car, with a four-kilogram difference between what was declared and what was found.

“The rules are clear,” Red Bull advisor Helmut Marko said via Auto Bild. “The mild punishment for that offence was a joke.

“It’s about fairness, about compliance with the rules and about the equal treatment of all the teams.

“Ferrari’s engine was questioned on several points which are probably beyond any grey area, but nothing was done to correct it.”

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Binotto again counter-argued claiming this was the first time any difference had been found despite being checked more than 10 times throughout this year.

However, Jos Verstappen, father of Red Bull driver Max, can't see how Ferrari would make such a simple error.

“You know that this was not a calculation error, Ferrari does not just make such calculation errors," he told Ziggo Sport.

“It is a sensitive subject in Formula 1, I do not want to burn my fingers on it. Next year, however, the rules really need to be tightened.”

Having opted not to protest about such technical matters this year, however, Marko claimed the team might not be so kind in 2020.

“If we suspect that there are any irregularities, we will definitely protest, and then Ferrari will have to disclose everything and the FIA deal with it accordingly,” he warned.

On the broader topic of managing the engine regulations, however, team boss Christian Horner praised the governing body's actions.

“They’re definitely doing everything they can to ensure that the complexity of these engines is policed in every area,” he said.

“And I think they’re just making more and more steps to ensure that grey areas are made very clear.

“I think going into the winter, the most important thing is clarity going into 2020," Horner added.

“And then hopefully the regulatory changes and technical directives coming in alleviate any concern.”