Mercedes has had to swap engines three times during pre-season testing, following a failure for Valtteri Bottas in the first test and an oil pressure anomaly for Hamilton this week.
The issues, on the back of problems for Williams, have left Mercedes with the task of getting on top of the reliability issues before the season opener in Melbourne next week.
Reflecting on how the team's pre-season testing programme had gone, Hamilton said that while the potential of the car was clear, the team was still not totally happy with how things were going.
"I think we've had a good winter test," he said. "But it's not been perfect, we've found that we've got plenty of problems that we are trying to iron out.
"I don't know how long it will take to iron out but that is never a bad thing necessarily to discover through testing.
"But otherwise, I think our performance has been quite good in the sense of laps we've got, the mileage, apart from yesterday, and the processes and things we discovered along the way. I've no idea where we stand compared to the others, the team will probably have a better idea of that."
Asked if the engine troubles were a worry, Hamilton said: "Is it a concern? Yeah. For sure.
"Normally in the pre-season we have much more confidence in the reliability so it has not been perfect. We are on our second or third engine.
"So it is definitely not an easy or relaxed scenario for us. But I have every confidence in the guys back at the factory that they can do the best job they can in the next two weeks to make sure we start on the right foot."
Beyond the reliability issues though, Hamilton said that the W11 was at least a car he felt comfortable in.
"I don't know where everyone else is, but I understand the car well," he said. "I am comfortable and confident in terms of getting a car in Melbourne and knowing that I can attack and extract the most from it. But if that's going to be enough to be ahead of the others we will find out."