New Zealand Warriors coach Ivan Cleary says it's a case of breaking some old habits as players adjust to the latest refereeing crackdown in the National Rugby League.

NRL referees coaches Bill Harrigan and Stuart Raper have adopted a "back to basics" approach as they look to ensure that fundamental rules of the game are adhered to in the coming season.

Under the new guidelines, match officials will penalise players for failing to play the ball with their foot or for moving off the mark, strictly enforce the onside rule at restarts and ensure scrums are properly bound.

The changes in interpretation were evident in the Warriors' two pre-season matches so far,

In the club's 24-4 win over Parramatta in Rotorua last weekend, referees Matt Cecchin and Gavin Reynolds dished out 19 penalties, many for play-the-ball infringements.

Cecchin and Reynolds have spent time with the Warriors this week to work with them on the changes, an exercise Cleary rated as enlightening.

"It's one thing to hear or read about it or get told, it's another thing to see some of the actual trigger points they look for, so it's been really enlightening, the last couple of days," he said.

"They've been really good in giving an understanding of what they look for and how much leeway they will give. Hopefully it transfers into the games."

While the effect of the changes at the moment might appear to be some pendantic refereeing decisions, Clearly said that, in the fairness to the officials, they were putting their foot down now so players knew what to expect when the competition proper began.

"I guess what they're looking for in the trials period is to change the players' mindsets so hopefully in round one there's less penalties purely because they're breaking some old habits," he said.

"That's all it is. We actually now have to break some habits that have been built up over the last few years."

Cleary felt his players were getting used to the revised interpretations, after having given away plenty of penalties while in possession both against the Eels and in the draw with Newcastle in Greymouth the previous weekend.

"That's a cardinal sin," he said of the turnovers.

"Hopefully we can get those down, but it's good it's in the trials. Certainly it gets everyone awake to it."