Less than two weeks after winning his fourth Formula One world title , Lewis Hamilton says he will not commit to the sport for much longer, as other challenges beckon.

The Mercedes driver finished ninth at the Mexican Grand Prix to secure the 2017 drivers' championship ahead of Ferrari rival Sebastian Vettel.

Attention among fans and observers quickly turned to debating Hamilton's chances of matching five-time winner Alain Prost or Michael Schumacher, who holds the record with seven F1 titles.

READ: F1 champ Hamilton avoided taxes on jet, according to leaks

But the 32-year-old Briton has been considering the impending prospect of life away from the grid.

"The question is how much longer [do] I want to commit to this sport," Hamilton told Globo Esporte ahead of this weekend's Brazilian GP.

"I know it won't be much longer because I also want to do other things like having a family and business. 

"There are other challenges for me."

In a separate interview with the F1 website on Thursday, Hamilton indicated his retirement plans will remain on the drawing board, at least for now.

"I am still a racing driver by heart and still have lots of fights in me," he said. "I believe I can win more championships – and if I have the car it should be possible."

Speaking ahead of this weekend's race at Interlagos, Hamilton's former team-mate Fernando Alonso offered a reminder that the Briton has not always enjoyed the advantages provided to him by Mercedes' superior technology in recent seasons.

ALSO READ: Felipe Massa announces retirement again

"Lewis is one of the greatest drivers in our sport and he showed that, especially in McLaren times when they were struggling," he said.

"For example in 2009 that car wasn't very good and he was still winning races. Those kind of performances put him at a very high level.

"The last three championships obviously the Mercedes has been the dominant car so they were a little bit easier, but he deserves the success that he is having now because he showed that talent many, many times."