F1: Wolff believes 21-race schedule is 'not feasible'

Formula One is pushing teams beyond breaking point by expanding the calendar to an unprecedented 21 races in 2016.

That is the warning of Mercedes team boss Toto Wolff, who said that although they once again dominated this year, the 19-race calendar pushed some team members to the brink.

"We have already seen that 19 races is pushing the physical and mental limits," Wolff told the German news agency SID in Stuttgart.

Wolff said adding another two events next year - the debut of the race in Azerbaijan, and Germany's return to the calendar - is simply too much.

"It is no longer possible in my opinion," the Austrian said. "This is simply no longer feasible."

The previous maximum number of races allowed under the provisions of the Concorde Agreement - 20 - was raised to 21 by a vote at the recent World Motor Sport Council meeting.

"This is a complex issue," Wolff added. "Maybe we need to introduce a second layer (of staff) in order to give our people some more recovery time.

"We want to get the maximum performance from the team, and that does not happen if they are working 365 days a year."