SAO PAULO -- Lewis Hamilton has backed local authorities to guarantee security during this weekend's Brazilian Formula One Grand Prix following recent problems at the Interlagos track.

Last year, members of Hamilton's Mercedes team were robbed at gunpoint after a practice session and in 2010 Jenson Button narrowly escaped a confrontation with heavily armed bandits.

"I have always been safe here in Brazil so I have not approached any races here with safety on my mind," Hamilton, who last month secured his fifth F1 drivers' championship, told reporters on Thursday. "I am confident F1 and the teams have taken action after last year."

The sport's governing body FIA said it has worked with local law enforcement authorities to step up security around the track and bolster police numbers.

"They took action to try and put things in place to improve it and I am assured," Hamilton said. "I do feel confident it is improved. We don't know what's around the corner but I am hopeful of a positive weekend for everyone."

Meanwhile, Hamilton said he was against moves to expand the F1 season, a day after officials confirmed that Vietnam would be added to the GP calendar in 2020.

"I'm somebody who really loves racing but the season is very long," the Briton said. "It's a big commitment for all of us and requires us to spend a long time away from our families. The calendar is getting longer and we are getting less time to rest," he added.