MONACO (AFP) - The Formula One drivers union on Saturday called for better safety measures on race circuits after the death of French driver Jules Bianchi.

Formula One must "never relent in improving safety," the Grand Prix Drivers Association (GPDA) said in a tribute to the 25-year-old Bianchi who died nine months after suffering critical brain injuries in a crash at the Japanese Grand Prix.

The GPDA called Bianchi "a great talent, a great man and a great friend."

"Twenty-one years after the deaths of Ayrton Senna and Roland Ratzenberger, we have now lost Jules, who has died as a direct consequence of an on track accident.

"It is at times like this that we are brutally reminded of how dangerous racing still remains.

"Despite considerable improvements, we, the Grand Prix drivers, owe it to the racing community, to the lost ones and to Jules, his family and friends, to never relent in improving safety."

Since the accident - in which Bianchi drove into a crane picking up another car - the International Automobile Federation has already ordered new measures to force drivers to slow down for accidents, including a "virtual safety car".