Mercedes boss Toto Wolff believes the FIA will find it "impossible" to replace Formula 1 race director Charlie Whiting with a single person.
Whiting died on the Thursday before the F1 season opener and the FIA reacted with emergency measures, moving Michael Masi into the race director role for the Australian Grand Prix.
The FIA is continuing to evaluate who will fill the role of race director long-term and Wolff says F1's bosses are now realising how difficult Whiting will be to replace.
"I think his [Charlie's] shoes are impossible to fill," said Wolff.
"I had a chat with Ross Brawn on the way to the [grid] photo and the minute of silence, and he said they just discovered how much Charlie was doing.
"[This includes] trivialities like the cameras in dangerous positions. This is what Ross mentioned to me.
"A bunch of tasks, and I didn't have any direction with the race director in the race.
"Certainly there will be tough decisions to take in the future, and I think it's impossible to replace Charlie.
"But whoever takes up that job, we need to support them."
The FIA used the experienced Masi, who was set to be F2 and F3 race director this year, as Whiting's stand-in at the Australian Grand Prix.
It is unclear if he will continue in the role for the short-term or if the governing body will look for somebody else.
FIA president Jean Todt said last weekend that talks would involve F1's teams.
"We are going to work very closely with the F1 teams and we have started to think," said Todt.
"Our team in Geneva is trying to see what we are going to implement for the future."