Max Verstappen has vented his frustration after yet another agonising failure ended his race early in Belgium.

The Dutchman suffered his sixth retirement in twelve races in front of his adoring fans at Spa, grinding to a halt on the Kemmel Straight on Lap 5.

Verstappen has only managed to score 67 points this season, but believes his woes cannot be dismissed as "bad luck".

"It is very frustrating, and especially in Belgium with lots of Dutch fans," he said. 

"To retire after eight laps is not acceptable. You can't call it bad luck. It is very bad.

"At the moment I am not a happy person. We will speak with the team and hope to do better in Monza."

The Bulls have been left lambasting engine suppliers Renault once again, with Christian Horner demanding an improvement.

"It really hurts and it really hurts Max because he's at his home race, huge support, he's in a great position and his engine has failed on him," the team principal said.

"That is hugely frustrating for him and of course the support group he has around him.

"That needs to change but unfortunately as a team it is an element that is beyond our control.

"So all we can do is put pressure on our supplier and say come on, get your act together."