The World Cup is shaping as a battle of wits between referees determined to exert greater control in key areas of games and players who will take advantage of any opportunities afforded to them in the law book.

International Rugby Board referees chief Paddy O'Brien has announced a crackdown in "five key areas" - the breakdown, scrum, the offside line, mauls and foul play - saying referees have "taken their foot off the throat" in recent months.

Five days away from Friday's start of this year's tournament, several leading players weighed in this weekend. They said the modern game demands they both play to the letter of the law while also seeking to take advantage of any leniency referees may show.

South African openside flank Francois Louw said all top players, particularly back rowers who contest possession of the tackled ball, learned to "play to the referee."

"That's the most important thing, to get a feel for the ref," Louw said. "Some guys have mastered it better than others. You can call it what you want but at the end of the day, if you get way with it you've done a good job."

New Zealand captain Richie McCaw, who is frequently accused of pushing the limit of the laws, expects players and referees to forge an understanding.

"That is always the way," he said. "You have got to know what you are allowed and not allowed to do. It would be silly to start giving away penalties or do anything stupid."

O'Brien said any hard-line policy at the World Cup will aim to make games faster, safer and more attractive.

Progress had been made in speeding up the game in 18 months since new refereeing interpretations were introduced. Those law changes came in after the 2007 World Cup, played under former laws which produced matches dominated by kicking and defense.

"The last 18 months we've reffed these areas well, but then we've taken the foot off the throat," O'Brien said. "We want quick ball at tackle and offside lines policed strictly. The theory there is, the team with the ball should have all the space available to them under the law."

O'Brien said referees would not be influenced by reputations some teams and players have for pushing the boundaries.

"What we want is for our referees not to go in with any prejudged ideas on any team and to go in and referee what's in front of them," he said. "We won't be influenced by what the media want. We'll be influenced by the way teams play in front of us."

And being as diplomatic as on-field officials always strive to be, former referee O'Brien adds: "Success for referees in this tournament will be if we're not talking about refereeing at the end of it."

SAPA-AP