UPDATE 3-Motor racing-Ferrari will quit F1 if 2010 rules stand

* Ferrari threaten to quit F1

* Champions unhappy with 2010 budget cap (adds FIA reaction para 11)

By Mark Meadows

MILAN, May 12 (Reuters) - Ferrari will quit Formula One at the end of this season if plans for a budget cap for 2010 are not abandoned, the champions said on Tuesday.

Toyota and Red Bull, who also own Ferrari-powered Toro Rosso, have already threatened not to enter next year's championship unless the new rules published by the governing International Automobile Federation (FIA) are changed.

"If the regulations adopted for 2010 will not change, then Ferrari does not intend to enter its cars in the next Formula One World Championship," a statement said.

The FIA, headed by Max Mosley, want to introduce an optional 40 million pound ($60.7 million) budget cap next year to encourage new teams to enter.

The plan would allow capped teams to operate with far greater technical freedom than those continuing with unlimited budgets.

Ferrari's president Luca di Montezemolo, head of the Formula One Teams' Association (FOTA), has warned it would create a two-tier championship that could be "fundamentally unfair and perhaps even biased".