The Formula One Teams' Association is to investigate claims that some teams overspent their allowed budgets last season.

Following Max Mosley's attempt at budget capping, in 2009 the teams came up with the Resource Restriction Agreement (RRA), which effectively limits budgets, staffing and resources.

Amongst themselves, and not part of the governing body's official regulations, the teams agreed to a sweeping number of changes that would place strict limits on various aspects of the sport, the reduction in testing being a good example.

However, in recent weeks there have been claims that Red Bull broke the agreement by going over its budget, a claim that team boss Christian Horner vehemently denies. "We've worked in accordance with the RRA limits since they were introduced," he told BBC Sport. "With tremendous hard work and internal efficiencies, we believe we've absolutely adhered to it.

"Red Bull has committed its budgets wisely," he continued, "and it's obviously surprising that people will feel that way, but it's inevitable, I guess, when you're at the front and winning races."

Speaking to the media today, Stefano Domenicali, who earlier revealed that he has stepped down as FOTA's vice-president, confirmed that the teams' alliance is investigating the claim, however, he said he was confident that all the teams had complied with the agreement.

Red Bull has submitted its accounts to FOTA and Horner admits that he expects them to be challenged.

"We expect other teams to potentially challenge (whether we have overspent) as they have done on front wings and ride heights and everything else in the course of last year, " he said. "But we don't have any issue. Red Bull probably has the third or fourth biggest budget in F1. We spent prudently and have achieved great efficiency within the factory, and we have to top that in 2011."

If a team should be found to have overspent its budget, under the agreement it would have its budget for the following year reduced accordingly.