Ferrari has slammed next year's proposed Formula One calendar, saying the schedule is "almost impossible" and has urged authorities to reduce the number of races by at least two.

Ferrari team manager Massimo Rivola said the mid-season sequence of Monaco, New Jersey and Montreal, with only one week's break between each, would cause a major logistical headache.

"It's going to be almost impossible to do it," Rivola said at the Korean Grand Prix on Friday.

"To be honest I'm still hoping we come back to the 20 races as per the current sporting regulation. At the moment the calendar is not the best calendar possible in terms of logistics.

"For sure there are some good commercial reasons behind this that I am not aware of."

The draft calendar for next year includes 22 races, though South Korea, New Jersey and Mexico are listed as provisional.

As well as additional races, next year will see the re-introduction of in-season testing, stretching teams' staffing levels and cost control.

Rivola said the freight and logistical costs are not necessarily easier on the major teams because they have more equipment and people to transport.

Sauber, a smaller, independent team, is also looking toward 2014 with trepidation.

"For us the biggest headache is definitely personnel because we, as a small team, we have to cover all races, tests and even demo events with the same number of people, the same crew," Sauber team manager Beat Zehnder said. "The more events you have, obviously the more difficult it gets.

"Then the triple-header; we would have to start packing up on Saturday in Monaco to make it to Jersey."

Andy Stevenson, team manager for Force India, said the planned four in-season tests will cost the team an additional $8 million, and said the team might skip one or more of those sessions unless more funding is forthcoming.

"With the resources we have available to us now, it won't be possible for us to attend the four tests as planned," Stevenson said. "We have brought to the table other options, cheaper options that wouldn't give us an advantage but they couldn't be agreed so we're either left with the choice of attending the test or not attending the test."