Six-time Formula One world champion Lewis Hamilton has hit out at drivers who failed to go along with his proposal for them to take a knee in solidarity with the Black Lives Matter movement ahead of the season-opening race in Austria, saying "silence is complicit".

Speaking before the race at the Red Bull Ring, where he finished fourth, the defending world champion spoke of his disappointment that a unanimous decision could not be reached among the 20 drivers.

"I just described that silence is complicit and there is still silence in some cases," said Hamilton, the only black driver among 20 competing for the world title this year.

"So, I thanked those that have said something on their social media platforms — because they have a great voice — and encouraged the others that have not, to say something.

"But I think it is part of a dialogue of people trying to understand, because there are still some people who don't fully understand what is happening and what is the reason for these protests and I continue to try to be that guide and try to influence as many people as I can with it."

Before the race, 14 drivers went down on one knee, and Hamilton wore a Black Lives Matter shirt. Ferrari's Charles Leclerc and Red Bull's Max Verstappen had already said that they would not be joining in, but stressed their support for the fight against racism. The others who declined to take part were Antonio Giovinazzi, Daniil Kvyat, Carlos Sainz and Kimi Raikkonen.

Apart from Hamilton, the only other non-white driver on the grid is British-born Thai driver Alexander Albon.

Before the season began, Hamilton made his feelings about the topic clear with a social media message to others significant players in the sport, saying "I know who you are and I see you".

The governing body of F1, the FIA, said it was up to teams and drivers to make a decision over what if any action they wanted to take, but it was agreed that all drivers would wear "end racism" t-shirts as they lined up for the pre-race Austrian national anthem, and a banner with the same message would be displayed prominently.

Hamilton's own Mercedes team cars have ditched their usual silver livery for all black this season, and a new diversity campaign in the sport has been given significant funding.

FIA President Jean Todt tweeted: "We must promote diversity in motor sport, and that is why we decided to give one million euros in contribution to the new dedicated Foundation created by F1. That is a first step, and more will come."