McLaren has apologised to Jenson Button for the reliability problems he experienced during Friday practice for the Bahrain Grand Prix and is hoping to have them fixed in time for a proper run in final practice.

Button stopped at Turn 1 on his third lap of the day when his car suffered an electronic shutdown and continued to have problems in FP2. Racing director Eric Boullier said it was a frustrating day for his driver and apologised to him.

"On the one hand, Fernando [Alonso] enjoyed a trouble-free morning followed by an equally unproblematic afternoon, running through his planned programme without mishap. On the other, Jenson was forced to endure a frustrating day, the result of not one but two major interruptions, compromising his ability to complete satisfactorily not only FP1 but also FP2. We apologise to him for that."

Honda boss Yasuhisa Arai gave more details on the problem.

"As for Jenson's power unit issues, we were limited on running time owing to an electrical shutdown in FP1. We were able to put the car back on the track for FP2, but the control data that monitors the power unit status was unstable and we had to bring the car back to the garage several times, which was unfortunate. We'll need to utilise tomorrow's FP3 to set the control data for qualifying."

Button added: "They got the car back pretty quickly which was good. The guys worked really hard, from P1 to P2 they did a great job, but we still had our problems in P2. "Then I went out on the soft tyre, I had to come back in, and then I went out on low fuel when everyone else was on high fuel, so it was difficult to get in any running, so not a great day. "There was a lot of useful data from the other car, but the frustrating thing is our cars were set up quite differently to get a lot of useful information about parts and what have you, and we weren't able to do that on our car. "It doesn't help either of us for tomorrow, but hopefully we've resolved the issues I've had."