Renault and Honda have confirmed they will be among the teams authorised to make performance improvements to their engines ahead of the 2009 season.

The FIA declared recently that some teams will be allowed to "equalise engine performance", following the emergence of a situation whereby some frozen-specification V8s have pulled ahead this year.

"We will have to present a project to the FIA with all the changes that we want to do, and they will have to approve them," Renault boss Flavio Briatore confirmed to the Spanish newspaper El Pais.

Honda's team CEO Nick Fry, meanwhile, explained that only some teams will get the green light to carry out work.

"For some, like McLaren, Ferrari and BMW, it is probably not necessary. But yes, I can confirm that we (Honda) will be able to do it."

It is believed that Toyota is the other carmaker likely to be approved for engine performance improvements.

Briatore, who argues that Renault has fallen as much as 30 horse power behind in the engine freeze, explained: "It is obvious that we will not be able to change the concept of the engine, but we will be able to modify some internal components.

"This year we are the team that has improved its car the most. With the improvement of our engine, in 2009 we will have a great single seater," the Italian vowed.