There are rumours of growing tension among Formula 1 drivers over Lewis Hamilton's recent political activism.

Having pushed hard over his support for the Black Lives Matter movement recently, the six-time world champion admitted he told his rivals at a meeting in Austria that "silence" on the issue of racism "is generally complicit".

The drivers have all agreed to wear 'End Racism" t-shirts on the grid on Sunday, but sources suggest at least five are refusing to vow to kneel in support of Black Lives Matter.

"Not everyone has decided what to do," admitted McLaren driver Carlos Sainz.

It is believed some drivers are upset with Hamilton's equating of 'silence' on matters of racial politics with a supposed racist element within the paddock.

"Well, we know there's an issue so we don't need an experience like tomorrow to prove that there is an issue," the 35-year-old said when asked about the apparent disagreement over 'taking a knee'.

Haas driver Kevin Magnussen said: "I intend to kneel - not so much because I support the Black Lives Matter organisation, but more because I want to support the worldwide movement against racism and discrimination.

"I hope no special group or organisation takes ownership of it," he added.