Engine chief Yasuhisa Arai admits his team struggled to cope in the early part of 2015, but said many of the issues Honda encountered stemmed from a lack of 'match sharpness' - an issue he is confident they have now overcome.
"Up until the Spanish Grand Prix in May, it was like playing whack-a-mole," Arai told Japan's Nikkei newspaper. "As soon as we resolved one problem, another popped up.
"We felt the effects of our seven-year absence from racing. Although we recognised [technological troubles], we failed to quickly pinpoint the causes, come up with measures to resolve them and make the necessary adjustments.
"Though we don't disclose the number of people involved in our F1 team, about half of them are new to the field. We were suffering from what athletes call a 'lack of match sharpness.'"
Asked about McLaren pushing for Honda to recruit 'outside' expertise, Arai explained: "We thoroughly discuss problems [with McLaren] until we see eye to eye. Sometime around last summer, they asked if we had sufficient [development] resources and wanted to know why we were doing things exclusively on our own. They also asked us to use outside personnel, which from their perspective is natural given the high job mobility in Europe.
"But we explained that Honda has a different philosophy. It's important to nurture manpower. It isn't acceptable to us to have an outside engineer stay for just three months or half a year."
Similarly, Arai said Honda would stand by their commitment to make the power unit as small as possible, adding: "F1 cars cannot go fast without proper consideration given to air resistance and the way suspensions move.
"It's important to minimise the size of power units so that they don't interfere with the car's design. McLaren once told us that we don't have to be aggressive in downsizing our power unit. But we are determined to shrink the size by whatever means possible.
"We're keen to meet everyone's expectations and reach the podium as soon as possible. We will resolve the technological problems we failed to address in 2015 and will head into the opening race with confidence."
McLaren will unveil their 2016 car, the MP4-31, on February 21 - the day before the start of pre-season testing at the Circuit de Barcelona-Catalunya in Spain.