The Japanese manufacturer faced a tough pre-season testing programme, with running at Barcelona affected by a spate of problems.

One of the biggest issues was a vibration of the car, which Hasegawa suggests was exacerbated by drivers running over kerbs.

"On the last two days of the second week [of testing], trouble was caused by the vibration of the car," said Hasegawa in Melbourne on Thursday.

"It was not only a problem with the engine itself, although the thing vibrating the most was the engine.

"The trouble caused cracks in a carbon pipe on the side of the car – with the harness getting detached. However, I don't know if these problems will not occur again if the engine vibrations stop. I am worried.

"It is also certain that the cars rode over the kerbs [in Barcelona] and this caused some vibration. If we have such a weakness in the side of the car, then it is worrying."

Honda says work on engine mapping that should improve the vibration issues has showed progress on the test bench, but the real situation would only be revealed once the cars were running on track.

"I think driveability is improving," added Hasegawa. "We have done some bench testing at Sakura, but we haven't run the engine on the track yet so I do not understand the situation as of today.

Other problems solved

Although there remains a question mark about the vibrations, Hasegawa said other issues that hit Honda in testing had been cured.

"In the Spanish test, trouble occurred in the oil tank on the first day of the first week, and the engine itself on the second day. I do not disclose what kind of trouble, but I have taken countermeasures," he said.

"On the first day of the second week, the high voltage systems were insulated against these problems, and I think that the big problem is solved.

"On the second day of the second week's test, there was a water leak in the radiator. That is why I turned off the engine."

Elaborating on the oil tank issue, he said: "It was a matter of design. There was a baffle plate inside, but it seems that it was not able to properly suck up oil, because its shape was bad.

"I have changed that. It was a shame that it was said that it was the only trouble, because it was a very rudimentary problem."

More power

Although Fernando Alonso complained about a lack of power on top of the reliability issues, Hasegawa insisted that the new engine is up on its 2016 performance figures.

However, he did concede that Honda had not hit the target it had hoped for.

"[Regarding] Alonso's power shortage and lack of speed compared with other cars, I do not know honestly. But I think that is our problem.

"We have not yet reached the target value we have established independently. But I cannot tell you the figures.

"I think that power is better than we had in Abu Dhabi last year, but the drag has increased. And as the tyres are wider, the driver may feel that the speed has dropped."

Additional reporting by Kunihiko Akai