LEWIS HAMILTON insists he is not surprised that his long-running rival Nico Rosberg has brought the curtain down on his Formula One career.

World champion Rosberg, 31, stunned the sporting world on Friday after he announced his decision to retire from grand prix racing just five days after clinching his maiden title.

But Hamilton, who has been competing against Rosberg ever since their formative racing years in karting, has claimed he was not taken aback by his Mercedes team-mate's decision.

"I'm probably one of the only people that it was not a surprise to," Hamilton, who is in Vienna alongside Rosberg at the FIA's end-of-season prize-giving ceremony, said.

"This is the first time he's won a title in 18 years, hence why it was not a surprise that he decided to stop.

"He's also got a family to focus on, and wants more children, and Formula One takes so much of your time. Will I miss the rivalry? Of course."

Hamilton's Mercedes team will begin the process of finding a replacement for Rosberg next week.

Ferrari's Sebastian Vettel, a winner of four titles, and McLaren driver Fernando Alonso, a double world champion, have been mooted as potential mouth-watering contenders.

Both drivers, however, are under contract with their respective teams for next season.

But Hamilton, making his first public appearance since he was threatened with disciplinary action by Mercedes following his controversial tactics at the season finale in Abu Dhabi, insists he is not bothered who partners him next term.

"It doesn't matter who they pick," Hamilton, 31, added. "I'll race them, and I'm here to race. Now the focus is obviously on next year and hoping for a better season.

"As long as we're treated fairly, it doesn't matter who is alongside you. Of course, we've got great team bosses who I'm sure will choose the right people to be representing the brand."

Pascal Wehrlein, the 22-year-old German, who is a member of the Mercedes young driver programme, is also in the frame. He has deputised for both Hamilton and Rosberg in testing.

"I'm interested to see who would want to be my team-mate, and respect anyone that would want to," Hamilton, the triple world champion, added.

"It should be someone who has to work well in the team. There will be stronger characters and less strong characters, and some drivers who take alternative routes in order to deal with competition.

"There will be good and better ones out there for sure, and I will be more than happy to help with that analysis."