Sean O'Brien believes the British and Irish Lions would have whitewashed New Zealand if they had been coached properly during a gruelling tour.

The Lions drew 1-1 with the world champions in a pulsating series, but O'Brien thinks it should have been a different story.

O'Brien started all three Tests against the All Blacks and feels he would have been celebrating a famous victory if Warren Gatland and his coaching staff had been up to the mark.

"I'd be pretty critical of it because I think we should have won the tour and we probably should have won it comfortably," O'Brien said on the Off The Ball podcast.

"The first week we definitely over-trained on the Thursday and maybe the coaches were panicking a little bit about getting the information into us. On the first week [before the first Test], we had a triple [session] day, lads' legs were heavy on the Thursday and we were playing the All Blacks on Saturday.

"We did nearly a similar thing in the last week. So maybe it's more a coaching point of view, in terms of taking lessons. Less is more sometimes on a tour like that, rather than trying to pick things up at the end of the week."

O'Brien was particularly unimpressed with backs coach Rob Howley.

"If I was being critical of any coach it would be the fact that I think Rob struggled with the group in terms of his attributes of trying to get stuff across, whereas Johnny [Sexton] and Owen [Farrell] drove everything the second week.

"The coaches have a lot to answer for in terms of our attack rather than Johnny and Faz trying to drive it. I think we should have won 3-0 with the players we had."