Ireland back row Sean O'Brien has criticised coaching and training methods during the British & Irish Lions' Test series against New Zealand, insisting the tourists should have beaten the All Blacks.

O'Brien, who played in all three Tests as the Lions secured a series draw, was particularly critical of a triple training session laid on by coaches less than two days prior to the first encounter with the All Blacks.

That match ended in a 30-15 defeat and the Leinster forward, who told Off The Ball that he aired his concerns about the workload at the time, believes overloading the players so close to the game was a mistake.

The Lions, coached by Warren Gatland in New Zealand, rebounded to win the second Test and then draw the third but O'Brien is adamant that the series was there to be won.

"To be honest, I'd be pretty critical of it because I think we should have won the tour and we probably should have won it comfortably," he said.

"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.

"We did nearly a similar thing in the last week. So maybe it's more [from] 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.

"And probably from a players' perspective, probably to be stronger and say 'look, we don't need that, we're ready to rock. We just need to be short and sharp'."

Sean O'Brien of the British & Irish Lions looks on after their third Test against New Zealand. Stephen McCarthy/Sportsfile via Getty Images

O'Brien was also critical of attack coach Rob Howley, suggesting that Johnny Sexton and Owen Farrell took it on themselves to decide the attacking game plan for the second and third Tests.

He said: "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 and Owen drove everything the second week, for instance, in our attack and had a better plan in place.

"So I don't know if it was people not buying into what he was about or whatever else.

"That's the hard thing about a Lions tour as well; getting everyone to listen to a coach that was probably set in his ways."

O'Brien admitted that the Lions can be proud of their efforts in New Zealand but says the strength of the squad at Gatland's disposal means anything less than a series win was a failure.

He added: "There's definitely proud moments in there. We can be proud of what we did out there at times.

"Not to be negative about it or anything, it was a great tour and everything. But at the end of the day I think, with the squad we had, we should have beaten them."