After a miserable return to F1 with McLaren in 2015, Honda made gains last term but remained adrift of rival manufacturers Mercedes, Ferrari and Renault.

McLaren technical director Tim Goss said earlier this month that Honda had completed a redesign of its power unit, aided by the abolition of the token system.

As Honda bids to close that gap still further, Hasegawa says the Japanese manufacturer is taking a risk with its next-generation unit.

"The concept is completely different," Hasegawa told Motorsport.com's sister publication Autosport. "It's very high-risk, we don't know a lot of things about that new concept.

"We know it will give us a performance advantage but the biggest risk is whether we can realise that potential this year."

The unit is set to feature a revised architecture and a new layout in a bid to improve performance and packaging based on lessons learned from the past two seasons.

Hasegawa said the internal combustion engine remains a key focus for Honda but development of other areas of the power unit is required in tandem to make progress.

"We need to concentrate on the ICE for this year," he said. "If we improve the engine itself, which means boosting exhaust gas energy, we need to boost the turbine otherwise we cannot perform at the same level in terms of deployment.

"We still have to do some tests and there will be some trial and error. I hope we have understood the direction and the elements to focus on.

"But it's not easy to combine the elements to realise the improvements on the ICE completely."

Listen to new Honda engine fire up at McLaren