Formula One losing its toughest race, says Hamilton

Formula One is losing one of its toughest races with the departure of Malaysia from the calendar after this weekend's grand prix, triple world champion Lewis Hamilton said on Tuesday.

The current contract at the Sepang circuit had been due to expire after next year's race but the Malaysian government and Formula One said in April this year's would be the last.

Malaysian Prime Minister Datuk Seri Najib Tun Razak said then that declining ticket sales, viewership and tourism were behind the decision.

The circuit has been on the calendar since 1999 and produced memorable races including Hamilton's win in 2014.

"It is definitely sad to think this is the last race," the Briton told a news conference organised by his Mercedes team's Malaysian oil sponsor Petronas.

"It's the most challenging for the car and the team, so they are taking away one of the toughest, if not the toughest, Grand Prix of the season, which will be hard to replace."

Some drivers liken the race to sitting in a sauna while wearing overalls. Cockpit temperatures approach 50 degrees Celsius and ambient humidity levels of around 70 per cent.

A driver loses around three litres of body fluid in sweat during the 90 minutes of an average Malaysian Grand Prix, according to Mercedes' data.

Hamilton had a nightmare at Sepang last year when he suffered an engine failure while leading the race from pole position.

The 25 points that slipped through his fingers ultimately proved crucial at the end of the season, when he lost the championship to team mate Nico Rosberg by five points.