Mercedes non-executive chairman Niki Lauda has revealed Lewis Hamilton and Nico Rosberg were at risk of being fired by the team in orders imposed after their collision during the 2016 Spanish Grand Prix.

The Austrian Formula 1 legend opened up about the frosty relationship between the two drivers, which reached rock bottom in their third consecutive year of fighting each other for the world title last season.

Though they had previously been friends since their karting days, Lauda claimed the severity of their rivalry meant they would only communicate with each other when they really had to.

"They had no relation, which is always bad," Lauda told Graham Bensinger in an interview on YouTube. "They were so bad that they didn't even say hello in the morning.

"I don't expect them to have breakfast together if they don't like each other, but the relationship was really bad. It affected Lewis mainly and Nico [as well], so it was fine but not easy."

It wasn't just between the drivers that tensioned flared as the triple world champion spoke about a disagreement he and Hamilton had in the wake of the 2016 incident at Spain, where the pair would collide at Turn 4 after Rosberg accidentally switched to a lower engine mode.

"The big question was whose fault was it?" Lauda said. "For me, it was clear because Lewis was too aggressive going to the right, hit the grass, couldn't stop his car and then hit him off.

"I said if I have to choose between the two it's more Lewis' fault than Nico's fault and Lewis did not appreciate that because he was of a different opinion. He said, 'Why do you criticize me?' I said, 'Excuse me. I cannot accept that you guys crash and then we have nothing and nobody's fault.

"For me, it has to be somebody's fault.' And then Lewis really got upset. Nico said, 'Yes, it was your part too, you moved to the inside. Why did you not leave room?' He said, 'Why should I, I was doing the race'."

The incident was the highest profile of many minor moments between the pair ranging from the contact at Spa in 2014 to the last lap move in Austria, just a handful of races after the Spain crash. 

With Mercedes' ultimate focus being on the Constructors' Championship, these comings together led to the team imposing the strongest possible threat to the two men.

"We told them, especially in Barcelona when they pushed each other off the track, we said this was unacceptable for Mercedes and one of you guys has to win [the race] you cannot push each other off.

"We had some rules put in, that you are not allowed to [do that] and you have to pay a penalty if you do it again or we will think of releasing you from your contract because we are team players here and we cannot destroy each other. This was the thing. Toto came up with some good rules and we had peace again. We fought hard and the accidents got reduced between them."

"This was the thing. Toto came up with some good rules and we had peace again. We fought hard and the accidents got reduced between them."

The thought of possibly cancelling a contract is particularly interesting after the events that would transpire in the season finale when Hamilton would ignore team orders to speed up as he looked to push Rosberg back into the cars behind.

In the immediate moments after, there were thoughts of potential ramifications for the 32-year-old but that all ended when five days later, Rosberg announced his retirement from F1.

Since then, Valtteri Bottas, who was brought in to replace the German has struck up a strong partnership with Hamilton, completing changing the atmosphere within Mercedes.