London: Formula One champions Mercedes will continue to give their drivers equal treatment despite the emergence of Sebastian Vettel as Ferrari's clear title contender, team boss Toto Wolff said on Tuesday.

Championship leader Vettel has won three of the six races so far, finishing second in the rest, and scored nearly twice as many points as team mate Kimi Raikkonen.

Mercedes have also won three races but they have been shared between Britain's triple champion Lewis Hamilton, with two victories but now 25 points behind Ferrari's German, and Finland's Valtteri Bottas.

"We have two excellent drivers and we will hold true to our philosophy of letting them race each other to drive the team forward - even if sometimes it can be difficult because you can't always have the one who is ahead in the championship winning," Wolff said in a team preview of Sunday's Canadian Grand Prix.

Hamilton, who was only seventh in the previous race in Monaco, has 104 points to Bottas's 75.

Both Mercedes drivers have gone well in Canada in the past, Hamilton winning for the last two years at the Circuit Gilles Villeneuve and five times in total -- making it his most successful circuit along with Hungary.

Bottas has also been on the podium in Canada for the last two years, with his previous team Williams.

Hamilton told reporters in Monaco, where Ferrari finished first and second, that it was clear to him that the Italian team were favouring Vettel.

"It's clear to me that Ferrari have chosen their number one driver," he said. "They are pushing everything to make sure Sebastian will maximise on all of his weekends."

The Briton added, however, that he saw no need to change Mercedes' approach.

"Valtteri has been doing a great job and I don't feel like we have to favour one over the other," he said. "We have to work collectively as a team more than ever before to beat the Ferraris in the constructors' (championship)." (REUTERS)