Lewis Hamilton refused to answer questions on his reasons for signing for Mercedes as he looks to focus on finishing his McLaren career as a world champion.

Hamilton's decision to leave McLaren at the end of the season after a 14-year working relationship has been the talk of the paddock ahead of this weekend's Japanese Grand Prix at Suzuka.

But when asked about why he had chosen to sign for the Silver Arrows, the 27-year-old said: "I don't want to talk about that this weekend. I have already spoken about that and I want to focus on this weekend."

Hamilton's reluctance to discuss his move did not prove popular with the international media, but the 2008 world champion appeared unmoved as he prepares for his final six races as a McLaren driver.

The 27-year-old currently trails championship leader Fernando Alonso by 52 points after retiring when leading the Singapore Grand Prix with a gearbox issue.

Hamilton has yet to taste victory at Suzuka, although he did win the 2007 Japanese Grand Prix, which was held at Fuji.

Hamilton admits he loves the popular figure-of-eight track and hopes to bounce back from his Singapore disappointment.

"I love coming here," he said. "The whole trip has been fantastic so far and the track is one of the best tracks in the world. It is not one that I have won at before but I think we have a car to win and hopefully it's a better weekend."

Hamilton's decision to leave McLaren has come as a disappointment to the team, but, when asked by Press Association Sport if he had spoken to his engineers and mechanics to explain his decision to leave, he said: "I have not spoken to them about it. This weekend it is business as usual. The focus is on trying to win and I know how professional they are."