Red Bull could part ways with Renault before their current deal expires as they "can't afford" another difficult season.

Renault have been largely blamed for Red Bull's failure to win a grand prix this year as their V6 engine has lacked both pace and reliability.

This has led to speculation that Red Bull could look elsewhere for engines with Mercedes reportedly topping the list.

And although Red Bull are contracted to Renault for next season, team boss Christian Horner says they cannot go on with the situation as it is.

"We can't afford to have another season like this season," he told Autosport.

"There is still a long way to go in this season, we're very working hard to turn it around.

"But it is very damaging and very expensive when you get into this scenario.

"We have put an awful lot of funding into the engine, we paid for the engine – it's not a free engine.

"When you're using a customer product, that's when frustration sometimes boils over."

The Brit admitted that Red Bull's decision could also rest on Renault's future plans as the latter is in talks to purchase the Lotus F1 team meaning Red Bull would be just another customer.

Horner added: "We have an agreement until 2016 and it's important to understand what Renault's plans are. Then we can react accordingly.

"We want to see what Renault's commitment is in the long term regarding Formula 1."