Warren Gatland has challenged referees to stop New Zealand's off-the-ball "blocking" in the British and Irish Lions Test series.
Head coach Gatland revealed the Lions have already raised the issue with officials ahead of the first Test at Auckland's Eden Park on Saturday.
Gatland will meet first Test referee Jaco Peyper on Friday to discuss the Lions' concerns further, in a bid for a clean opening clash with the All Blacks.
"The frustrating thing for us is the amount of blocking that's going on," Gatland said "It makes it difficult to complete attacking opportunities and situations.
"There is so much happening off the ball in terms of holding players or subtly holding players. We've raised it with the referees already.
"If you listen to the ref mic, they were talking about it constantly through the game. They gave a couple of penalties (in Saturday's 32-10 win over the Maori) for blocking.
"It's one of the hardest things to pick up because it tends to happen quite a long way off the ball. In fairness to the assistant referees, they did raise it on a number of occasions.
"And sometimes it was put through to the TMO (television match official), who said it didn't have a material effect and told the referee to talk to the players about it. We'll keep raising it.
"Because it was picked up on a couple of occasions (on Saturday) they stopped doing it as much.
"That made it a lot easier for us to get up in the air and to compete. In a couple of games we haven't been able to get up in the air because there has been that interference."
Gatland believes the Lions have been denied a number of try-scoring opportunities because of subtle blocking lines, especially against the Maori.
Asked if the Lions had been stymied, the 53-year-old said: "Absolutely, yeah. When you go back and look at the tapes and look at all the stuff off the ball, where someone's run a line or stopped someone getting through, some of it is very subtle.
"That's made it difficult. It's part of the game in New Zealand. Some of the referees are picking them up for that.
"We've just got to handle that and just hope the referees, the assistant referees and the TMOs pick up what's going on.
"For us, it's being smart, and hopefully the officials are aware of it.
"I am happy enough that if the referees are aware of it and they pick up teams for that, that would be good."
The All Blacks have tried to call the Lions' bluff by suggesting Gatland's teams are one-dimensional - but the tourists' boss insisted he will not lose his nerve ahead of the Test series.
England let hubris and Australian taunts goad them out of their bullish 10-man game in the 1991 World Cup final, adding width to their play only to trip up 12-6 in a match they could so well have won by trusting their strengths.
When Gatland was asked if there would be any danger of the Lions reacting to New Zealand's jibes, the Lions boss replied: "Like England in 1991? No.
"We're still working on some of the connections in terms of the forwards and when we go out the back and when we play front line, where we think we can still get better and stress opposition teams a little bit more.
"I was pleased with the performance (against the Maori). I thought it was an outstanding display of rugby and I don't know what more you can do in sending a message to someone in terms of how good we could be, but we won't be going out there to play differently."