Honda is aiming to leave behind the dubious honour of being Formula 1's least powerful engine supplier by the end of the season.

Despite swirling speculation about the future of the McLaren-Honda collaboration, the Japanese manufacturer has vowed to keep improving its 2017 power unit.

McLaren-Honda had a good, technical trouble-free weekend and post-race test in Hungary, and plans are now afoot for Honda's 'spec 4' upgrade after the August break.

"We can continue to improve in terms of performance," said Honda's Yusuke Hasegawa, "but it will be difficult to catch Ferrari and Mercedes.

"But by the end of the season, we want to move past Renault," the Japanese is quoted as saying by Speed Week.

"The drivers are now happy with the driveability of the engine, we just have to have more power. We're working on that now."

McLaren intend to make a decision about their 2018 engine supplier in September, but team boss Eric Boullier backed Hasegawa in the plans for the rest of this year.

"After half the season, we are working hard to at least regain our competitiveness of last year," he is quoted as saying by Spain's El Confidencial.

The season resumes with the Belgian Grand Prix on August 27.