McLaren Racing CEO Zak Brown has admitted the team could be forced to make a 'business decision' and split from Honda because it can no longer justify the manufacturer's investment when compared to its loss of prize money and sponsors.

After seven races, McLaren is yet to score a point in a season dogged by lacklustre performance and woeful reliability, a situation compounded further during the Canadian Grand Prix when Fernando Alonso retired with an engine failure from tenth position with just two laps remaining.

The latest issue comes amidst growing speculation McLaren is seeking to end its deal with Honda in favour of a switch back to Mercedes power in an effort to improve fortunes and convince star driver Alonso to stay beyond 2017.

Indeed, though McLaren has previously stayed tight-lipped on the Mercedes rumours, Brown revealed in Montreal that one of the key benefits for continuing with Honda - the sizeable finance it brings - is now outweighed by the ongoing losses in prize money and reluctance of sponsors to invest.

"I think it just becomes a business decision," he said. "As nice as the Honda contract is and I'm sure there's lots of teams here that would love to have the contractual relationship, at the end of the day you start losing a lot of money in prize money which is all easily documented. We lost sponsor partners to other teams.

With Brown actively seeking to secure a title sponsor for McLaren for 2018, he admits the Honda difficulties have now taken its toll on its portfolio that cannot continue.

"You've got two different types of sponsor losses, you have those that leave the sport, sometimes you don't know if that was you or the sport or circumstances, but when someone leaves a team to go to another team what that means is they are happy with the sport, they're not happy with the team.

"We've had more of those in the last couple of years than we've probably had - and maybe not statistically - in the last decade.

"So when you start adding that up it starts to offset the positive element of the contractual relationship with Honda where we are getting those revenues we're depositing, there's not outgoing, obviously that's not the case with a lot of the teams here."

Should McLaren ends its relationship with Honda, the Japanese firm would still have interest in F1 having signed a deal to supply engines to Sauber for 2018.