McLaren-Honda could be shaping up to clash with Formula 1's governing body over the new engine regulations.

Fabrice Lom, the FIA's engine chief, said in Barcelona that the rules now say teams potentially left without an engine next year will be supplied by the manufacturer with the fewest customers.

As the only Hondas on the grid are in the works McLaren cars, that would put the Japanese carmaker in the hotseat.

"Of course, this is not only about McLaren, it is relevant to everyone," Lom said.

"I think everyone will be happy to implement this agreement."

However, McLaren supremo Ron Dennis is insisting that he has a watertight contract with Honda guaranteeing him an exclusive supply of Japanese power.

Team boss Eric Boullier confirmed to La Derniere Heure newspaper: "No regulations oblige us on this matter.

"I think Ron has told the FIA that we can do it only when we are world champions."

So it appears that the FIA is headed towards potential conflict with McLaren, with the regulations on one hand and the team's Honda contract on the other.

"Honestly, I don't think I can answer that question. I'm sorry," said Lom when asked for clarity.

When asked by Spain's AS newspaper if F1 might see the first Honda engine customer in 2017, Honda's Yusuke Hasegawa answered: "At the moment, we don't know.

"The 2017 regulations on the power units has already been fixed, but we need to wait and see. In principle, Honda is and has always been open to supplying customer teams."

The 2016 season continues with the Spanish Grand Prix tomorrow.