Warren Gatland has accused Super Rugby teams of illegal scrummaging following the Lions' victory over the Crusaders in Christchurch on Saturday night.

The Crusaders were consistently penalised at scrum time with French referee Mathieu Raynal awarding at least five penalties to the Lions at the set piece.

Lions coach Warren Gatland said they were caught out because the referee was ruling to the letter of the law.

"The ruling says you must have a small gap," Gatland said.

"At Super Rugby, they preload. We've practiced for both scenarios having come to New Zealand so we've prepared to fully preload and we've also practiced to have a slight gap as well, depending on how the referee interprets it.

"The law says there must be a small gap, they don't play to the law of the game, Super Rugby sides tend to scrummage illegally if that's the case."

The scrum calls appeared to baffled Crusaders' front rowers Joe Moody, Codie Taylor and Owen Franks.

Despite appearing to have the dominant scrum, Gatland said the Crusaders had one scrum maximum where they had the ascendancy.

In the post-match wash-up, the interpretations has seen the referee come under increasing pressure.

Pressure that Gatland said was completely unwarranted.

"I thought [the referee] did a good job and I didn't have any issues with that," Gatland said.

"It's not something I'm concerned about. I'm a little surprised a huge amount has been made about the scrum."

After Saturday night, the scrum will be an area of great contention for the rest of the tour with the set piece a core staple of the Lions' game.

With two out of the three Tests controlled by French referees, the All Blacks will also likely make sure they're preparing for all interpretations at scrum time.

Newshub.