Nine Formula One teams have signed a voluntary deal to limit testing to 30 days during the Grand Prix season.
But Ferrari have opted not to sign the agreement, which is restricted to European circuits approved by the sport's governing body, the FIA.
Teams will not be able to test at more than one circuit on the same day or with more than two cars.
"We've had enough time to know Ferrari don't favour this sort of agreement," said Minardi's Paul Stoddart.
The agreement also specifies that teams will remain barred from using circuits that host an event on the calendar, with the exception of Silverstone, Barcelona and Monza.
A reason for Ferrari's non-participation is that they have their own tracks in Italy and sometimes test on three circuits on the same day.
Team boss Jean Todt also said recently that they expected to save over £2m by organising tests for 2005 that would require 15 fewer team members.
Last week, it had been suggested that BAR would also opt out of the cost-cutting agreement, although team chief Nick Fry was quick to dispel those rumours.
"I think now there is a good level of agreement between all the Formula One teams, perhaps except Ferrari, that 30 days is the agreed amount," he said last Monday.
"It was suggested partly by us anyway, so 30 is the number."