"Everyone acknowledges that the scrums are an ongoing concern for rugby," O'Brien said in Dunedin yesterday.
"The laws are quite simple but they are not so easy to carry out. Overall, the scrums are being refereed well.
"We as a rugby group, all of us, have to look at where we can change the scrum."
O'Brien, in Dunedin for a symposium on applied high-performance physical conditioning organised by the Otago Institute of Sport and Adventure at the Otago Polytechnic, said changes to the scrum were brought in in 2007 for the safety of the players.
"It is a lot better. It's just not pleasing on the eye," he said.
O'Brien emphasised there will not be any changes to the rules of the game until after the world cup. After that, the coaches, players and referees will get together and review where the game is at.
"I'm sure that the scrum will be the main focus," he said. "It is the one area of the game that is not good and will be reviewed."
O'Brien is happy with the other areas of the game, including the breakdown.
"Everyone has talked about the breakdown for the last 100 years," he said.
"But the quality of rugby we are seeing at the moment is outstanding and one of the beauties of the game is the breakdown.
"To change it again would be silly. I think some of the commentators have more problems with the breakdown than the players and the referees. It is not something that needs to be changed."
One area the IRB has asked referees to police more vigilantly is offside around the fringes and from kicks.
"When we put our foot down on that the game improved," O'Brien explained. "The referees may have slipped back a bit in not being so vigilant , but come the world cup that will be the focus again."
O'Brien is happy with the referees that have been selected to officiate at the world cup. He does not expect every referee to be perfect, "but I am confident that every referee will do their best.
"That is all we can ask."
O'Brien has been the IRB referees manager since 2005 and is based in Dublin. He lives in New Zealand during the southern hemisphere season.
He will be in Italy for the next six weeks for the Under-20 World Cup, then back in New Zealand for the Tri-Nations and the world cup.
Matt Blair, of the Otago Polytechnic, hasbeen the fitness and conditioning coach for international referees for the last three years.
"The fitness standard of referees now is way beyond what it was in the past," O'Brien said.
The Paddy O'Brien File
IRB rugby referees board manager Paddy O'Brien at the high-performance physical conditioning symposium at the Otago Polytechnic in Dunedin yesterday.
• Age: 51.
• Home town: Invercargill.
• Base: Dublin.
• Refereed: NZ record of 37 tests (1994-2005).
• Occupations: NZ Police, professional referee (1994-2005), manager IRB's Referees Board (from 2005).
• Honours: Officer NZ Order of Merit.
