The Toyota Formula 1 team has sided with Renault F1 in the trackside spat about the legality of formula one engines.

First team boss Flavio Briatore, and then Renault racer Fernando Alonso, griped this week that they believe the French squad has fallen behind its competitors because of the 'freeze' on most engine development.

While they say Renault really did cease tinkering with its homologated 2.4 litre unit, some outfits - possibly including Ferrari and McLaren - continued making performance steps in the guise of allowable tweaks to improve reliability or reduce costs.

It is believed that, like Mercedes-Benz and Ferrari, BMW have also made permissible changes to its homologated engine.

"From the Toyota side, we have obviously had the same approach as Renault -- that means more legal than legal," the Japanese squad's Pascal Vasselon said in Hungary.

"It was an engine freeze, our engine has been frozen," he added.