The former world champions Renault followed Ferrari's lead yesterday and threatened to pull out of Formula One at the end of the season unless the governing body rewrites the 2010 rules.
"If the decisions announced by the [FIA] World Council on the 29th of April 2009 are not revised, we have no choice but to withdraw from the FIA Formula One world championship at the end of 2009," managing director Flavio Briatore said in a statement.
Constructors' champions Ferrari, Formula One's glamour team who have competed in every championship since 1950, issued a similar threat on Tuesday in response to the proposal to introduce an optional £40m budget cap.
Toyota and the two Red Bull-owned teams – Red Bull Racing and Scuderia Toro Rosso – have also said they cannot enter what would amount to a two-tier championship, meaning half of the sport's 10 existing teams have now threatened to leave. The stance of the teams has raised the stakes considerably in a war of words with the governing FIA, led by Max Mosley.
Ferrari's president, Luca di Montezemolo, and the teams are scheduled to meet the Briton and Formula One's commercial supremo Bernie Ecclestone at a hotel near Heathrow airport in London tomorrow.
"I hope common sense will prevail because the last thing we want to do is lose any of the manufacturers or teams currently in Formula One," Ecclestone said. He has also said Formula One and Ferrari need each other.
Under the 2010 regulations, those teams accepting the cap would have far greater technical freedom than those continuing with unlimited budgets in order to level the playing field and encourage new entrants. Renault, champions with Spaniard Fernando Alonso in 2005 and 2006, said they had been forced to reconsider because of the risk of a two-tier series. The French manufacturer also expressed frustration the FIA had "completely ignored" the Formula One Teams Association's (FOTA) own cost-saving proposals.
"Our aim is to reduce costs while maintaining the high standards that make Formula One one of the most prestigious brands on the market," said Briatore. "We want to achieve this in a co-ordinated manner with the regulatory and commercial bodies, and we refuse to accept unilateral governance handed out by the FIA."
Toyota's motorsport president John Howett, the FOTA vice-chairman, said: "If you consider the single thread running through all teams' similar statements it is a wish to establish a correct and proper basis of governance for the sport," he said. "The priority for the future is a process of governance which ensures all competitors compete under the same rules, that the regulations are stable and which establishes a platform from which costs can be sensibly and actively reduced without destroying the core DNA of the sport."